Grilled Steak Crostini with Horseradish Sauce Recipe

Let me tell you about the Grilled Steak Crostini with Horseradish Sauce recipe — it’s truly one of those bites that just feels special without any fuss. Imagine tender, juicy filet mignon kissed by the grill, paired with a creamy, tangy horseradish sauce that wakes up your palate. This recipe works like a charm for casual dinner parties or when you want to impress guests without spending all night in the kitchen.

I’ve made this dish more times than I can count, usually when friends drop by last minute or when we’re craving something fancy yet comforting. The magic is in how the rich steak and punchy horseradish sauce balance perfectly on crisp crostini, making each bite irresistible. If you love bold flavors with a little elegance, this Grilled Steak Crostini with Horseradish Sauce recipe will become one of your go-tos too.

Ingredients You’ll Need

Each ingredient in this recipe plays a starring role, coming together to create a symphony of flavors and textures. When shopping, aim for fresh, quality steak and day-old baguette for best crostini crunch.

• Filet Mignon Steaks: Choose fresh, high-quality cuts for tenderness; the mild flavor lets the horseradish sauce shine.
• Olive Oil: Used for grilling and crostini, pick extra virgin if you can for richer flavor.
• Steak Seasoning: A blend of herbs and spices that enhances the steak’s natural taste; feel free to use your favorite or make your own.
• Sour Cream: The creamy base for the horseradish sauce, lending a cool balance to its sharp kick.
• Prepared Horseradish: Adds that signature tangy zing; adjust the amount based on your heat preference.
• Dijon Mustard: Gives the sauce a smooth, slightly spicy undertone that pairs beautifully with horseradish.
• Champagne Vinegar: Light and bright, it lifts the sauce without overwhelming it.
• Worcestershire Sauce: Adds umami depth to the horseradish sauce, making it irresistible.
• Fresh Chives: Their mild onion flavor freshens the sauce and garnishes the onions.
• Baguette (day old): Slightly stale is perfect for crisp, golden crostini.
• Butter: Melted for brushing the crostini – it helps achieve that irresistible crunch and flavor.
• Garlic: Optional but highly recommended to rub on crostini for a subtle aromatic punch.
• Onion: Caramelized slowly to sweet perfection, balancing the savory steak and spicy sauce.
• Sugar: Just a pinch helps boost the natural sweetness of the onions as they cook.
• Kosher Salt and Pepper: Essential seasonings to enhance every layer of flavor.
• Balsamic Glaze: Optional finishing touch that adds a sweet tangy drizzle over the top.

Variations

I love tinkering with this Grilled Steak Crostini with Horseradish Sauce recipe depending on the season, the crowd, or what’s in my fridge. Personalizing it makes the dish feel even more comforting and yours.

• Change the cut of steak: I’ve swapped filet mignon for ribeye or sirloin when I wanted a bolder beef flavor – just adjust the cooking time for thickness.
• Make it spicy: Toss in a pinch of cayenne or replace the horseradish with wasabi for a different heat profile I really enjoy when serving adventurous eaters.
• Vegetarian version: Swap sliced grilled portobello mushrooms for steak—grilled with the same seasoning—and keep the horseradish sauce for a punchy finish.
• Herb twist: Adding fresh thyme or rosemary to the steak seasoning gives a woodsy aroma that upgrades the flavor effortlessly.
• Gluten-free crostini: Use gluten-free baguette or sturdy veggie slices like grilled zucchini rounds to keep everyone happy at the table.

How to Make Grilled Steak Crostini with Horseradish Sauce Recipe

Step 1: Season and Grill the Steak to Perfection

Start by patting your filet mignon steaks dry—this helps the seasoning stick and ensures a great sear. Rub the steaks lightly with olive oil and sprinkle your steak seasoning generously on both sides. Preheat your grill or grill pan to high heat; you want that instant sizzle as soon as the steak hits the surface. Cook for about 4-5 minutes per side for medium-rare, but depending on steak thickness, adjust timing. Remember to let the steak rest for at least 5 minutes before slicing thinly—this keeps those juices locked in and the meat tender.

Step 2: Prepare the Horseradish Sauce

While the steak rests, whisk together sour cream, prepared horseradish, dijon mustard, champagne vinegar, Worcestershire sauce, and chopped fresh chives in a bowl. Taste and season with salt and pepper accordingly. I find letting this sauce chill in the fridge for even 10-15 minutes really helps the flavors marry and deepen.

Step 3: Caramelize the Onions Slowly

Heat olive oil and butter in a sauté pan over medium-low heat, then add your diced onion and sprinkle a pinch of sugar. Stir occasionally and be patient—this process takes about 20-25 minutes for onions to become golden, sweet, and melt-in-your-mouth. Season lightly with kosher salt and if you want, stir in chopped chives near the end for freshness. This step adds such a lovely, rich sweetness that contrasts beautifully with the horseradish sauce’s tang.

Step 4: Make the Crostini

Brush the baguette slices on both sides with melted butter and olive oil mixture. If you’re using garlic, rub the smashed clove over one side of each slice before grilling or toasting. I use a grill pan or regular skillet over medium heat, turning frequently until the crostini are crispy and golden—about 3-4 minutes total. Crispy, flavorful crostini are the perfect base for this appetizer.

Step 5: Assemble Your Crostini

On each toasted baguette slice, spread a generous spoonful of the horseradish sauce, add a few thin slices of the grilled steak, and then top with caramelized onions. If you like, drizzle a little balsamic glaze over the top for a touch of sweetness and acidity that rounds out the flavors. Garnish with extra chopped chives for color and fresh bite.

How to Serve Grilled Steak Crostini with Horseradish Sauce Recipe

Garnishes

Fresh chives are my go-to garnish here—they add just the right pop of green and subtle onion flavor. Sometimes I sprinkle a few red pepper flakes for more heat or add a few microgreens if I want a bit of extra freshness. A drizzle of high-quality balsamic glaze gives it that pretty glossy finish that everyone admires before biting in.

Side Dishes

I often serve these crostini with a simple mixed green salad dressed in lemon vinaigrette to cut through the richness. Roasted veggies like asparagus or Brussels sprouts also pair beautifully if you want something warm alongside. For a party, I keep it simple so guests can grab these as finger foods without distraction.

Creative Ways to Present

For special occasions, I’ve arranged these crostini on a large wooden board alongside small bowls of extra sauce and caramelized onions so everyone can customize their bites. Another time, I used mini baguettes as a fun twist, making smaller versions perfect for cocktail parties. It’s a versatile recipe that looks just as great as it tastes!

Make Ahead and Storage

Storing Leftovers

After assembling, if you have leftovers, store the steak slices, horseradish sauce, and caramelized onions separately in airtight containers in the fridge. This keeps each component fresh and prevents the crostini from getting soggy if pre-assembled. I like to keep the crostini plain and re-toast them before serving again.

Freezing

The steak and caramelized onions freeze fairly well if you want to make extras. I recommend portioning them into freezer-safe containers or bags and thawing overnight in the fridge. I don’t freeze the crostini or horseradish sauce since texture and flavor can suffer.

Reheating

To reheat leftover steak, gently warm in a skillet over medium-low heat to keep it tender. Re-crisp your crostini in the oven or toaster oven for a few minutes at 350°F. The caramelized onions can be reheated on the stovetop or microwave and stirred into the crostini right before serving. Reassemble fresh with the horseradish sauce for best flavor!

FAQs

Final Thoughts

This Grilled Steak Crostini with Horseradish Sauce recipe holds a special place in my kitchen repertoire because it manages to be both elegant and approachable—perfect for impressing friends or indulging in a rich, flavorful snack. I can’t recommend it enough if you want something quick to assemble but bursting with layers of interest and boldness. Trust me, once you try these crostini, they’ll become a favorite for entertaining and solo treats alike. Go ahead, fire up that grill and let the flavors do their magic!

Grilled Steak Crostini with Horseradish Sauce Recipe

★★★★★ 4.4 from 208 reviews

• Author: Isabella
• Prep Time: 15 minutes
• Cook Time: 35 minutes
• Total Time: 50 minutes
• Yield: 8 crostini 1x
• Category: Appetizer
• Method: Grilling
• Cuisine: American

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Description

Grilled Steak Crostini with Horseradish Sauce offers a delicious appetizer featuring tender filet mignon, served atop crisp baguette slices with creamy horseradish sauce, caramelized onions, and flavorful toppings. Perfect for gatherings or special occasions, these crostini combine smoky grilled steak with savory, tangy, and sweet elements for a sophisticated bite.

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Ingredients

Scale 1x2x3x

For the Steak

• 8 ounces Filet Mignon Steaks
• 2 tablespoons olive oil, if desired
• 2 tablespoons Steak Seasoning

For the Horseradish Sauce

• 1 cup sour cream
• 1/4 cup prepared horseradish
• 1 1/2 tablespoons dijon mustard
• 1 teaspoon champagne vinegar
• 1 teaspoon worcestershire sauce
• 1/2 tablespoon fresh chopped chives
• salt and pepper, to taste

For the Crostini

• 1 Day old Baguette, cut into 1/4 inch slices
• 2 tablespoons butter, melted
• 1/4 cup olive oil
• 1 garlic clove, smashed, optional

For the Caramelized Onions

• 1 onion, diced
• 1 tablespoon olive oil
• 1/2 tablespoon butter
• 1/4 teaspoon sugar
• Kosher salt, to taste
• Chopped Fresh Chives, optional
• Balsamic Glaze, optional

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Instructions

1. Prepare the Steak: Rub the filet mignon steaks with olive oil (if using) and season generously with steak seasoning. Preheat a grill or grill pan over medium-high heat and cook the steaks to your desired level of doneness, about 4-5 minutes per side for medium rare. Remove from heat and let rest.
2. Make the Horseradish Sauce: In a bowl, combine sour cream, prepared horseradish, dijon mustard, champagne vinegar, worcestershire sauce, and chopped chives. Mix well and season with salt and pepper to taste. Refrigerate until ready to serve.
3. Prepare the Crostini: Preheat your oven to 375°F (190°C). Arrange the baguette slices on a baking sheet. Brush each slice with melted butter and olive oil mixture. Optional: rub each slice with a smashed garlic clove for extra flavor. Bake for 10-12 minutes or until crisp and golden.
4. Caramelize the Onions: Heat olive oil and butter in a skillet over medium heat. Add the diced onions and sprinkle with sugar and kosher salt. Cook slowly, stirring occasionally, until onions are deeply golden and caramelized, about 20-25 minutes. Remove from heat and optionally stir in chopped fresh chives.
5. Assemble the Crostini: Thinly slice the rested steak. Spread a layer of horseradish sauce over each crostini. Top with sliced steak, a spoonful of caramelized onions, and drizzle with balsamic glaze if desired. Garnish with extra chives for color and flavor.

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Notes

• Use day-old baguette for the best texture when making crostini; fresh bread can be too soft.
• Adjust horseradish amount to taste as it can be quite potent.
• The balsamic glaze adds a sweet acidity that complements the richness of the steak and onions perfectly but is optional.
• Letting the steak rest after grilling ensures juicy slices.
• Caramelize onions slowly for the best flavor development; high heat can burn them.

Keywords: steak crostini, grilled steak appetizer, horseradish sauce recipe, caramelized onions, easy starter, party appetizer