Easy Steak Crostini with Creamy Horseradish Sauce

Steak Crostini with Creamy Horseradish Sauce brings together tender slices of grilled steak, golden toasted baguette, sweet caramelized onions, and a tangy horseradish cream for the ultimate party appetizer. Each bite delivers the perfect mix of savory, creamy, and crunchy — a restaurant-style starter you can easily make at home in under an hour.

Why You’ll Love This Steak Crostini

If you’re looking for an appetizer that impresses without stress, this steak crostini is a must-try. The grilled filet mignon melts in your mouth, while the caramelized onions and creamy horseradish sauce elevate every bite with bold flavor. The toasted crostini add the ideal crunch, creating a crowd-pleasing balance of textures and tastes. Perfect for holidays, date nights, or elegant gatherings, it’s a dish that looks fancy but couldn’t be simpler to prepare.

You’ll love it because it’s

• Easy to prepare and assemble
• Packed with rich, layered flavors
• Great for entertaining and make-ahead prep
• Customizable with lighter or vegetarian substitutions

Easy Steak Crostini with Creamy Horseradish Sauce

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• Author: Dolly
• Total Time: 50 minutes
• Yield: 20 crostini

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Description

Steak Crostini with Creamy Horseradish Sauce combines tender grilled steak slices, toasted baguette rounds, sweet caramelized onions, and a tangy horseradish cream. The perfect elegant appetizer for holidays, date nights, or gatherings.

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Ingredients

• 8 ounces filet mignon (or sirloin)
• 2 tablespoons olive oil
• 2 tablespoons steak seasoning or salt and pepper
• 1 cup sour cream (or Greek yogurt)
• ¼ cup prepared horseradish
• 1½ tablespoons Dijon mustard
• 1 teaspoon champagne vinegar
• 1 teaspoon Worcestershire sauce
• ½ tablespoon chopped chives
• Salt and pepper, to taste
• 1 day-old baguette, sliced ¼-inch thick
• 2 tablespoons melted butter
• ¼ cup olive oil
• 1 garlic clove, smashed (optional)
• 1 large onion, diced
• 1 tablespoon olive oil
• ½ tablespoon butter
• ¼ teaspoon sugar
• Kosher salt, to taste
• Balsamic glaze drizzle (optional)
• Fresh chopped chives (optional)

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Instructions

1. Preheat grill to 450°F (232°C). Pat steak dry, season with olive oil, salt, and pepper. Grill 4–5 minutes per side until 125°F for medium-rare. Rest 10 minutes before slicing.
2. In a bowl, mix sour cream, horseradish, Dijon, vinegar, Worcestershire, chives, salt, and pepper. Chill until ready to use.
3. Preheat oven to 375°F (190°C). Slice baguette and brush with butter, olive oil, and garlic. Bake 5 minutes per side until golden. Cool completely.
4. Heat olive oil and butter in a skillet. Add diced onions, cook 10 minutes, then add sugar and salt. Continue cooking until soft and golden, about 20 minutes total. Cool slightly.
5. Spread 1 teaspoon horseradish sauce on each crostini. Top with sliced steak and caramelized onions. Drizzle balsamic glaze and sprinkle chives. Serve warm or at room temperature.

Notes

Make ahead by preparing steak, onions, and sauce in advance. Assemble just before serving for best texture and flavor. For a vegetarian option, use grilled portobello mushrooms.

• Prep Time: 20 minutes
• Cook Time: 30 minutes
• Category: Appetizer
• Method: Grilled
• Cuisine: American

Ingredients for Steak Crostini

For the Steak

• 8 ounces filet mignon (or sirloin for budget-friendly option)
• 2 tablespoons olive oil
• 2 tablespoons steak seasoning or a mix of salt and pepper

For the Horseradish Sauce

• 1 cup sour cream (or Greek yogurt for a lighter twist)
• ¼ cup prepared horseradish
• 1½ tablespoons Dijon mustard
• 1 teaspoon champagne vinegar (or white wine vinegar)
• 1 teaspoon Worcestershire sauce (or soy sauce for alcohol-free)
• ½ tablespoon fresh chopped chives
• Salt and pepper, to taste

For the Crostini

• 1 day-old baguette, cut into ¼-inch slices
• 2 tablespoons melted butter
• ¼ cup olive oil
• 1 garlic clove, smashed (optional)

For the Caramelized Onions

• 1 large onion, diced
• 1 tablespoon olive oil
• ½ tablespoon butter
• ¼ teaspoon sugar
• Kosher salt, to taste

Optional Garnishes

• Balsamic glaze drizzle
• Fresh chopped chives

Ingredient Notes

• Filet Mignon: Tender and buttery, but any well-marbled steak (sirloin, ribeye, flank) works beautifully. For a vegetarian twist, try grilled portobello mushrooms.
• Horseradish Sauce: The tangy cream complements the steak’s richness. Adjust the horseradish level based on your spice preference.
• Crostini Bread: Slightly stale baguette slices toast more evenly and hold up well under toppings.
• Onions: Caramelize them low and slow for 15–20 minutes to draw out natural sweetness — it’s worth the patience.
• Sauce Substitution: Use Greek yogurt instead of sour cream for a protein-rich option.

Step-by-Step Instructions

Step 1 – Grill the Steak

1. Preheat a gas grill to 450°F (232°C), or prepare a hot charcoal fire.
2. Pat steaks dry with paper towels and season with salt, pepper, and olive oil.
3. Grill for 4–5 minutes per side, closing the lid for even heat.
4. Remove when the internal temperature reaches 125°F for medium-rare.
5. Transfer to a plate, cover loosely with foil, and let rest for 10 minutes before slicing.

Pro Tip: Resting locks in the juices for tender, flavorful steak slices.

Step 2 – Make the Horseradish Sauce

1. In a small bowl, combine sour cream, horseradish, Dijon mustard, champagne vinegar, Worcestershire sauce, and chives.
2. Season with salt and pepper, then mix until smooth.
3. Cover and refrigerate until ready to assemble.

Tip: The sauce can be made a day ahead — it actually tastes better after chilling.

Step 3 – Toast the Crostini

1. Preheat oven to 375°F (190°C).
2. Slice baguette into ¼-inch-thick rounds.
3. Mix melted butter, olive oil, and smashed garlic in a bowl.
4. Brush both sides of the bread slices, arrange them on a baking sheet, and bake for 5 minutes.
5. Flip and bake another 3–4 minutes until golden and crisp.
6. Cool completely before topping.

Step 4 – Caramelize the Onions

1. Heat olive oil and butter in a skillet over medium heat.
2. Add diced onions and cook, stirring every few minutes.
3. After 10 minutes, sprinkle in sugar and a pinch of salt.
4. Continue cooking another 10 minutes until onions are soft, golden, and fragrant.
5. Set aside to cool slightly.

Step 5 – Assemble the Crostini

1. Spread about 1 teaspoon of horseradish sauce onto each crostini.
2. Slice the rested steak thinly against the grain and place one piece atop the sauce.
3. Spoon a small amount of caramelized onion on each piece.
4. Finish with a drizzle of balsamic glaze and a sprinkle of chives for color.

Serve immediately while warm or at room temperature.

Pro Tips for Success

• Make Ahead: You can prepare all the components (steak, onions, sauce, crostini) in advance. Assemble just before serving.
• Perfect Doneness: Use a meat thermometer for accuracy — 125°F (medium-rare) or 135°F (medium).
• Crostini Texture: Avoid overbaking; they should be crisp yet not rock-hard.
• Balanced Flavors: Taste and adjust your horseradish sauce before assembly. The tang should complement, not overpower.
• Presentation: Arrange on a platter with parsley or microgreens for a restaurant-style look.

Flavor Variations

1. Blue Cheese Twist: Add a small crumble of blue cheese before topping with steak.
2. Garlic Butter Steak Crostini: Brush bread with garlic butter before toasting for extra depth.
3. Balsamic Reduction Drizzle: Replace glaze with homemade balsamic reduction for a sweet-tart finish.
4. Mushroom Lover’s Version: Substitute steak with sautéed portobello mushrooms and drizzle truffle oil.
5. Holiday Herb Crostini: Add rosemary or thyme-infused oil to the sauce for a festive flavor.

Serving Suggestions

• Serve on a large platter as part of a charcuterie-style spread.
• Pair with sparkling wine, cider, or iced tea for a balanced menu.
• Add fresh greens or roasted veggies to make it a light meal.
• For a crowd, double the recipe — guests always come back for seconds!

Storage and Freezing Instructions

• Refrigerate: Store leftover steak, onions, and sauce separately in airtight containers for up to 3 days.
• Reheat: Warm steak slices gently in a skillet over low heat. Toast crostini briefly in the oven before serving.
• Freeze: You can freeze caramelized onions for up to 1 month; thaw in the refrigerator before use.
• Avoid Freezing Crostini: They lose their crunch — it’s best to make them fresh.

Nutrition Facts (Per Serving)

(Values are approximate and based on one crostini.)

FAQ About Steak Crostini

How far in advance can I make steak crostini?

You can make all components a day ahead — the steak, onions, and sauce store well separately. Assemble the crostini just before serving to keep the bread crisp and the toppings fresh.

Can I use a different cut of steak?

Absolutely. Sirloin, ribeye, or flank steak all work beautifully. Just adjust the grill time slightly based on thickness to maintain tenderness.

What if I don’t have a grill?

You can sear the steak in a cast-iron skillet on the stovetop. Cook for 4–5 minutes per side over medium-high heat and rest before slicing.

Is there a lighter or low-fat option?

Yes! Swap sour cream for nonfat Greek yogurt and brush crostini with olive oil instead of butter. You’ll keep the creamy texture with fewer calories.

Can I make it vegetarian?

Definitely. Replace the steak with grilled portobello mushrooms or marinated tofu slices — both pair perfectly with the horseradish sauce.

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Final Thoughts

These Easy Steak Crostini with Creamy Horseradish Sauce are everything you want in an appetizer: flavorful, elegant, and deceptively simple. Each bite offers a delightful contrast of warm, juicy steak, cool tangy cream, and crisp toasted bread. Whether you’re hosting a dinner party or serving snacks at a holiday gathering, this recipe will make your guests feel like they’re enjoying a chef-prepared treat — right from your kitchen.