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Close-up of multiple delicious Steak Crostini with Horseradish Sauce appetizers garnished with fresh herbs on a wooden board.
Maryam

Steak Crostini with Creamy Horseradish Sauce

Tender slices of perfectly cooked steak rest atop crispy toasted crostini, all brought together with a zesty, creamy horseradish sauce. This elegant appetizer is sure to impress your guests with its rich flavors and sophisticated presentation.
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Prep Time 25 minutes
Cook Time 20 minutes
Total Time 45 minutes
Servings: 16 pieces
Course: Appetizer
Cuisine: American
Calories: 180
Ingredients Equipment Method Notes

Ingredients
  

For the Creamy Horseradish Sauce
  • 1/2 cup sour cream full-fat
  • 2 tbsp prepared horseradish drained slightly if very wet
  • 1 tbsp fresh chives finely minced
  • 1 tsp Dijon mustard
  • 1/2 tsp lemon juice freshly squeezed
  • Pinch salt
  • Pinch black pepper freshly ground
For the Steak
  • 1 lb sirloin or flank steak about 1-inch thick
  • 1 tbsp olive oil
  • 1 tsp kosher salt
  • 1/2 tsp black pepper freshly ground
For the Crostini
  • 1 baguette day-old, sliced into 1/2-inch rounds (about 20-24 slices)
  • 2 tbsp olive oil
  • Pinch salt
  • Pinch black pepper freshly ground
For Garnish
  • 1 tbsp fresh chives finely minced

Equipment

  • Mixing Bowl
  • Small Whisk
  • Large Skillet (cast iron preferred)
  • Baking Sheet
  • Sharp knife
  • Cutting board
  • Tongs

Method
 

Prepare the Creamy Horseradish Sauce
  1. In a small mixing bowl, combine the sour cream, prepared horseradish, minced chives, Dijon mustard, fresh lemon juice, salt, and black pepper.
  2. Whisk until thoroughly combined and smooth. Taste and adjust seasoning if needed.
  3. Cover and refrigerate for at least 15 minutes to allow flavors to meld, or up to 2 hours.
Cook the Steak
  1. Pat the steak dry thoroughly with paper towels. Season generously on both sides with kosher salt and freshly ground black pepper.
  2. Heat the olive oil in a large cast-iron skillet over medium-high heat until shimmering and almost smoking. Ensure the pan is very hot before adding the steak.
  3. Carefully place the steak in the hot skillet. Sear for 3-4 minutes per side for medium-rare (internal temperature 130-135°F), or longer for your desired doneness. Use tongs to flip.
  4. Remove the steak from the skillet and place it on a cutting board. Tent loosely with foil and let it rest for at least 5-10 minutes. This is crucial for juicy, tender steak.
  5. After resting, slice the steak very thinly against the grain. Then, cut these slices into smaller, bite-sized pieces suitable for crostini.
Prepare the Crostini
  1. Preheat your oven to 375°F (190°C).
  2. Arrange the baguette slices in a single layer on a baking sheet.
  3. Drizzle or lightly brush each slice with olive oil. Season lightly with salt and pepper.
  4. Bake for 8-12 minutes, or until golden brown and crisp. Keep a close eye on them to prevent burning as oven temperatures can vary.
  5. Remove from oven and let cool slightly.
Assemble the Steak Crostini
  1. Spread a generous dollop of the creamy horseradish sauce onto each toasted crostini.
  2. Top each crostini with a few slices of the thinly cut steak.
  3. Garnish with additional fresh minced chives.
  4. Serve immediately and enjoy!

Notes

For best results, allow the horseradish sauce to chill for at least 15-30 minutes before serving, as the flavors meld beautifully. The steak can be cooked a few hours in advance and reheated gently or served at room temperature. For crispier crostini, ensure the baguette slices are from a day-old baguette. If serving a larger crowd, consider having a warming tray for the steak slices to keep them at an optimal temperature.