Description
Toasty baguette slices topped with seared beef, sweet caramelized onions, and a creamy horseradish aioli make an elegant and delicious appetizer.
Ingredients
Scale
- 1 French baguette, sliced into 1/2-inch rounds
- 2 tablespoons olive oil, divided
- 1 large yellow onion, thinly sliced
- 1/2 teaspoon salt, divided
- 1/4 teaspoon black pepper, divided
- 1/2 teaspoon fresh thyme leaves (or 1/4 teaspoon dried)
- 1 pound beef tenderloin or sirloin steak, thinly sliced
- 1/2 cup mayonnaise
- 1 tablespoon prepared horseradish
- 1 teaspoon Dijon mustard
- 1 clove garlic, minced
- 1 tablespoon chopped fresh chives (optional, for garnish)
Instructions
- Preheat oven to 375°F (190°C). Arrange baguette slices on a baking sheet, brush lightly with olive oil (about 1 tablespoon total), and bake for 8–10 minutes until golden and crisp. Set aside.
- In a large skillet over medium heat, add remaining 1 tablespoon olive oil. Add sliced onion and cook, stirring occasionally, for 15–20 minutes until soft and caramelized. Season with 1/4 teaspoon salt, 1/8 teaspoon pepper, and thyme. Remove to a bowl.
- In the same skillet over medium-high heat, add beef slices in a single layer (work in batches if needed). Sear 1–2 minutes per side until browned but still tender. Season with remaining 1/4 teaspoon salt and 1/8 teaspoon pepper. Remove from heat.
- In a small bowl, stir together mayonnaise, horseradish, Dijon mustard, and garlic until smooth.
- To assemble: Spread a small amount of horseradish aioli on each crostini. Top with a spoonful of caramelized onions, then a slice of beef. Garnish with chives if desired. Serve immediately.
Notes
For best results, let the caramelized onions cool slightly before assembling to prevent the crostini from becoming soggy. You can also use ribeye or flank steak as a substitute for tenderloin.
Nutrition
- Calories: 220
- Sugar: 3 g
- Fat: 13 g
- Carbohydrates: 14 g
- Protein: 12 g