I often prepare components for these steak crostini ahead for easy entertaining throughout the week. The caramelized onions and horseradish sauce actually improve when made in advance, letting you assemble quickly before serving.
There is something magical about bite sized food that feels both elegant and approachable. These Steak Crostini with Horseradish Sauce & Caramelized Onions capture that perfect balance. Crispy bread, tender beef, sweet onions, and a zesty sauce come together in one harmonious bite that always disappears first at gatherings.
I first fell in love with this combination years ago at a friends holiday party, where a platter of these crostini sat beside a wine station. Watching guests create their own perfect bites while chatting and laughing made me realize this was more than just an appetizer. It was a conversation starter, a way to bring people together over shared enjoyment of good food.
What makes these Steak Crostini with Horseradish Sauce & Caramelized Onions so special is how each component can be prepared in advance, making them perfect for stress free entertaining. Whether you are hosting a wine party, planning Christmas friends party food, or simply want an impressive appies night at home, this recipe delivers both flavor and convenience.
Table of Contents
Steak Crostini with Horseradish Sauce & Caramelized Onions
These elegant Steak Crostini feature crispy baguette slices topped with tender steak, sweet caramelized onions, and a zesty horseradish sauce. Perfect for entertaining, these bite sized appetizers can be partially prepared ahead for stress free hosting.
- Prep Time: 25 minutes
- Cook Time: 45 minutes
- Total Time: 1 hour 10 minutes
- Yield: 20–24 crostini 1x
- Category: Appetizer
- Method: Stovetop, Oven
- Cuisine: American
Ingredients
- For the caramelized onions:
- 2 large yellow onions, thinly sliced
- 2 tablespoons butter
- 1 tablespoon olive oil
- 1 teaspoon brown sugar
- 2 tablespoons balsamic vinegar
- Salt and pepper to taste
- For the horseradish sauce:
- 1/2 cup sour cream
- 1/4 cup mayonnaise
- 2 tablespoons prepared horseradish
- 1 teaspoon Dijon mustard
- 1 tablespoon fresh chives, chopped
- Salt and black pepper to taste
- For the steak and assembly:
- 1 pound flank steak, ribeye, or sirloin
- 1 baguette, sliced into 1/2 inch thick pieces
- 2 tablespoons olive oil
- 1 garlic clove, peeled
- Fresh parsley or chives for garnish
- Salt and black pepper for seasoning
Instructions
- Prepare the Caramelized Onions: Heat butter and olive oil in a large skillet over medium low heat. Add sliced onions and cook slowly, stirring occasionally, for about 25 30 minutes until deeply golden and sweet. Add brown sugar and balsamic vinegar during the last 5 minutes of cooking. Season with salt and pepper.
- Make the Horseradish Sauce: While onions are cooking, combine sour cream, mayonnaise, horseradish, Dijon mustard, and chopped chives in a small bowl. Season with salt and pepper. Cover and refrigerate until ready to use.
- Cook the Steak: Pat steak dry with paper towels and season generously with salt and pepper on both sides. Heat a tablespoon of olive oil in a heavy skillet over medium high heat. Cook steak for 4 6 minutes per side for medium rare, depending on thickness. Transfer to a cutting board and let rest for at least 10 minutes before slicing thinly against the grain.
- Toast the Baguette Slices: Brush baguette slices lightly with olive oil and toast in a 375°F oven for 8 10 minutes until golden and crisp. Rub each slice with the peeled garlic clove while still warm for extra flavor.
- Assemble the Steak Crostini: Spread a teaspoon of horseradish sauce on each toasted baguette slice. Top with a few slices of steak, a spoonful of caramelized onions, and a sprinkle of fresh herbs. Arrange on a platter and serve immediately.
Notes
Components can be prepared ahead: caramelized onions keep for 5 days, horseradish sauce for 1 week, and cooked steak for 3 4 days. Assemble just before serving to maintain crispy texture. For gluten free option, use gluten free baguette. Leftover prime rib works beautifully in place of fresh steak.
Nutrition
- Serving Size: 2 crostini
- Calories: 280
- Sugar: 5g
- Fat: 12g
- Carbohydrates: 22g
- Fiber: 2g
- Protein: 18g
Ingredients List
Steak Crostini with Horseradish Sauce & Caramelized Onions brings together simple ingredients that create extraordinary flavor. Here is what you will need.
For the caramelized onions:
2 large yellow onions, thinly sliced
2 tablespoons butter
1 tablespoon olive oil
1 teaspoon brown sugar
2 tablespoons balsamic vinegar
Salt and pepper to taste
For the horseradish sauce:
1/2 cup sour cream
1/4 cup mayonnaise
2 tablespoons prepared horseradish
1 teaspoon Dijon mustard
1 tablespoon fresh chives, chopped
Salt and black pepper to taste
For the steak and assembly:
1 pound flank steak, ribeye, or sirloin
1 baguette, sliced into 1/2 inch thick pieces
2 tablespoons olive oil
1 garlic clove, peeled
Fresh parsley or chives for garnish
Salt and black pepper for seasoning
Smart substitutions:
Use leftover prime rib or roast beef instead of cooking fresh steak
Swap sour cream with Greek yogurt for a tangier horseradish sauce
Try ciabatta or gluten free bread for the crostini base
Add blue cheese crumbles for a different flavor profile
Timing
Prep time: 25 minutes
Cook time: 45 minutes
Total time: 1 hour 10 minutes
While the total time might seem substantial, remember that much of this involves hands off cooking. The caramelized onions need about 30 minutes of slow cooking but require minimal attention. Compared to many meat party appetizers that demand last minute preparation, these Steak Crostini with Horseradish Sauce & Caramelized Onions actually become easier when you break the components into manageable steps.
Step-by-Step Instructions
Prepare the Caramelized Onions
Heat butter and olive oil in a large skillet over medium low heat. Add sliced onions and cook slowly, stirring occasionally, for about 25 30 minutes until deeply golden and sweet. The slow cooking is essential for developing that rich, complex flavor. Add brown sugar and balsamic vinegar during the last 5 minutes of cooking. Season with salt and pepper. These can be made up to 3 days in advance.
Make the Horseradish Sauce
While onions are cooking, combine sour cream, mayonnaise, horseradish, Dijon mustard, and chopped chives in a small bowl. Season with salt and pepper. Cover and refrigerate until ready to use. The sauce flavors meld and improve with at least 30 minutes of chilling time.
Cook the Steak
Pat steak dry with paper towels and season generously with salt and pepper on both sides. Heat a tablespoon of olive oil in a heavy skillet over medium high heat. Cook steak for 4 6 minutes per side for medium rare, depending on thickness. Transfer to a cutting board and let rest for at least 10 minutes before slicing thinly against the grain.
Toast the Baguette Slices
Brush baguette slices lightly with olive oil and toast in a 375°F oven for 8 10 minutes until golden and crisp. Rub each slice with the peeled garlic clove while still warm for extra flavor.
Assemble the Steak Crostini
Spread a teaspoon of horseradish sauce on each toasted baguette slice. Top with a few slices of steak, a spoonful of caramelized onions, and a sprinkle of fresh herbs. Arrange on a platter and serve immediately.
Nutritional Information
Per serving (2 crostini):
Calories: 280
Protein: 18g
Carbohydrates: 22g
Fat: 12g
Fiber: 2g
Sugar: 5g
The steak provides high quality protein and iron, while the onions offer antioxidants and prebiotic benefits. The horseradish contains compounds that may support sinus and respiratory health. These Steak Crostini with Horseradish Sauce & Caramelized Onions balance indulgence with nutritional value, making them a satisfying choice for winter crostini appetizers.
Equipment Needed
Large skillet for caramelizing onions
Small mixing bowl for horseradish sauce
Baking sheet for toasting baguette slices
Sharp knife for slicing steak and onions
Cutting board
Measuring spoons and cups
No special equipment required for these Steak Crostini with Horseradish Sauce & Caramelized Onions. A good heavy bottomed skillet will help with even cooking of both the steak and onions, but even a basic non stick pan will work perfectly fine.
Why You Will Love This Recipe
Perfect for entertaining: These crostini look impressive but come together with manageable steps. The make ahead components mean you can enjoy your own party rather than being stuck in the kitchen.
Versatile for any occasion: Whether you need wine snacks appetizers for a casual gathering or holiday crostini appetizers for Christmas dinner, this recipe adapts beautifully.
Customizable to preferences: Guests can build their own bites, adjusting the ratio of steak to onions to sauce. This interactive element makes them perfect for appies night with friends.
Excellent use of leftovers: This recipe transforms leftover prime rib or steak into something new and exciting. The prime rib appetizer holidays version is particularly luxurious.
Balanced flavors and textures: The combination of crispy bread, tender steak, sweet onions, and zesty sauce creates a perfect bite every time. These Steak Crostini with Horseradish Sauce & Caramelized Onions deliver restaurant quality flavor in your own kitchen.
Healthier Alternatives
For gluten free needs: Use gluten free baguette or rice crackers as the base. The steak and toppings are naturally gluten free.
Lower carb option: Serve the steak, onions, and sauce as a deconstructed platter without the bread, or use cucumber slices as the base.
Lighter horseradish sauce: Substitute Greek yogurt for both the sour cream and mayonnaise. The tanginess pairs beautifully with the horseradish.
Reduced fat version: Use cooking spray instead of oil for toasting the baguette and reduce the butter in the onions by half. The flavor will still be excellent.
Vegetarian adaptation: Replace the steak with grilled portobello mushrooms or roasted vegetables. The caramelized onions and horseradish sauce work wonderfully with vegetarian options too.
Serving Suggestions
These Steak Crostini with Horseradish Sauce & Caramelized Onions shine as the centerpiece of any appetizer spread. For wine party food ideas, pair with a bold red wine like Cabernet Sauvignon or Malbec. The wine s tannins complement the rich beef and cut through the creamy sauce.
For holiday entertaining, arrange these alongside other festive bites like my Bruschetta Dip or Buffalo Chicken Sliders. The variety ensures there is something for every guest.
Consider setting up a build your own crostini station with separate bowls of steak slices, caramelized onions, horseradish sauce, and additional toppings like arugula or blue cheese crumbles. This interactive approach works beautifully for Christmas friends party food where mingling is key.
For a complete appies night, serve these steak bites alongside my High Protein Slow Cooker Garlic Butter Beef Bites for a meat lover s dream platter. Add some fresh vegetables and dip for balance.
Common Mistakes to Avoid
Rushing the onions: Caramelizing onions properly takes time. Cooking them over too high heat will burn the sugars rather than developing that deep, sweet flavor. Low and slow is the only way.
Overcooking the steak: Since the steak is sliced thin on crostini, it can become tough if overcooked. Aim for medium rare and remember it will continue cooking slightly while resting.
Skipping the garlic rub: That quick rub of raw garlic on the warm toasted bread adds incredible flavor depth to your Steak Crostini with Horseradish Sauce & Caramelized Onions. Do not skip this simple step.
Using bread that is too thick: Baguette slices should be about 1/2 inch thick. Thicker slices become difficult to bite into, while thinner ones might not support the toppings.
Assembling too early: While components can be prepared ahead, assemble the crostini just before serving to prevent the bread from becoming soggy. The crispy texture is part of what makes these winter crostini appetizers so delightful.
Storing Tips
Store components separately in airtight containers in the refrigerator. The caramelized onions will keep for up to 5 days, while the horseradish sauce stays fresh for about a week. Cooked steak can be refrigerated for 3 4 days.
The assembled Steak Crostini with Horseradish Sauce & Caramelized Onions do not store well as the bread becomes soggy. However, you can toast extra baguette slices and freeze them in a zip top bag for up to 3 months.
To reheat components, warm the steak briefly in a skillet over medium heat and bring the onions to room temperature or warm gently. The horseradish sauce should always be served cold.
For prime rib appetizer holidays, if using leftover prime rib, slice it thin and bring to room temperature before assembling. The gentle warmth will make the fat slightly creamy and luxurious.
Conclusion
These Steak Crostini with Horseradish Sauce & Caramelized Onions represent everything I love about home cooking. They transform simple ingredients into something special, bring people together around good food, and create lasting memories in the process. The combination of flavors and textures never fails to impress, while the make ahead nature keeps entertaining stress free.
Whether you are planning an intimate appies night or a large holiday gathering, this recipe delivers both in flavor and practicality. The components work beautifully together, each playing its part in creating that perfect bite that keeps guests coming back for more.
I would love to hear how your Steak Crostini with Horseradish Sauce & Caramelized Onions turn out. Share your experience in the comments below, and if you are looking for more crowd pleasing appetizers, try my Family Friendly Italian Grinder Sliders or this irresistible Baked Garlic Bread Dip. Happy cooking.
FAQs about Steak Crostini with Horseradish Sauce & Caramelized Onions
What cut of steak is best for Steak Crostini?
Lean, tender cuts like flank steak, sirloin, or tenderloin are ideal. They cook quickly and can be sliced thinly against the grain for optimal tenderness on a crostini.
How can I prevent my Steak Crostini from getting soggy?
Toast the bread until crisp, and assemble the crostini just before serving. You can also create a barrier by spreading the horseradish sauce or a thin layer of cream cheese on the crostini first, before adding the steak and onions.
Can Steak Crostini with Horseradish Sauce & Caramelized Onions be made ahead of time?
Partially. The caramelized onions and horseradish sauce can be made 1-2 days in advance. The steak can be cooked and sliced a few hours prior, but for best results, toast the crostini and assemble immediately before serving to maintain crispness.
What’s the best way to caramelize onions for crostini?
Slice onions thinly and cook them slowly over low to medium-low heat with a little oil or butter. This gradual process allows their natural sugars to develop a rich, sweet, and golden-brown flavor, which typically takes 30-45 minutes.
How do I make a simple horseradish sauce for steak crostini?
Combine prepared horseradish with sour cream, mayonnaise, or crème fraîche. Season with a touch of Dijon mustard, lemon juice, salt, and pepper to taste. Adjust horseradish quantity for desired heat.
Is Steak Crostini served warm, cold, or at room temperature?
For optimal enjoyment, steak crostini is best served slightly warm or at room temperature. The steak itself can be served warm, but assembling it on freshly toasted bread allows for the best texture contrast.
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