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Steak Crostini with Creamy Horseradish Sauce and Caramelized Onions Recipe
Ben Carraoli

Steak Crostini with Creamy Horseradish Sauce and Caramelized Onions Recipe

I love creating appetizers that feel fancy but are surprisingly simple to make at home. This Steak Crostini with Creamy Horseradish Sauce and Caramelized Onions quickly became a favorite for me. The combination of juicy, tender steak, sweet caramelized onions, and the zing of horseradish is irresistible. I often make it for cocktail parties, family gatherings, or even a cozy date night at home
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Total Time 1 hour
Ingredients Method Notes

Ingredients
  

  • Filet mignon or beef tenderloin – Choose high-quality meat for tenderness. Let it come to room temperature for even cooking.
  • Unsalted butter – Allows better control of seasoning and helps in caramelizing onions.
  • Garlic powder – Prevents burning compared to fresh garlic and adds subtle flavor.
  • Dried thyme – Pairs beautifully with beef and enhances aroma.
  • Salt and black pepper – Season generously to bring out the natural flavors.
  • Baguette – A narrow round baguette works best for even, well-shaped crostini.
  • Olive oil – Use a good-quality oil; it adds flavor and ensures golden crispy bread.
  • Mayonnaise – Thick and creamy base for a smooth sauce.
  • Prepared horseradish – Adjust amount based on your spice preference.
  • Dijon mustard – Adds tang and depth.
  • Lemon juice – Fresh lemon balances the richness of the sauce.
  • Shallots – Sweeter and milder than regular onions.
  • Balsamic vinegar – Adds sharpness and enhances the golden color.
  • Brown sugar – Sweetens and balances the tangy flavors.
  • Salt and black pepper – Season as needed for perfect flavor.

Method
 

  1. I start by sprinkling the steak with salt, black pepper, garlic powder, and thyme. Letting it rest for at least 30 minutes allows the flavors to penetrate deeply, ensuring a juicy bite.
  2. In a bowl, I whisk together mayonnaise, horseradish, Dijon mustard, and fresh lemon juice. Season to taste and refrigerate until assembly—it’s simple but packs a punch of flavor.
  3. I melt butter in a saucepan, add the shallots, and cook gently until soft. Then I stir in balsamic vinegar, brown sugar, salt, and pepper, letting them caramelize into a golden, sweet topping over 30 minutes.
  4. I sear the steak in olive oil over medium-high heat to my preferred doneness. Resting it for 15 minutes afterward ensures the meat stays tender and juicy before slicing thinly.
  5. I brush baguette slices with olive oil and bake them at 375°F for 5–7 minutes until golden. They’re crisp, perfect for holding all the toppings.
  6. I spread the horseradish sauce on each crostini, add thin slices of steak, and top with caramelized shallots. A few fresh herbs like thyme or parsley make it look stunning and add freshness.

Notes

  • I always rest the steak; it makes the meat melt-in-your-mouth tender.
  • Using day-old bread ensures extra crispy crostini.
  • Slicing steak thinly against the grain gives a more elegant bite.
  • Preparing onions and sauce a day ahead saves stress on the day of serving.
  • Watch the shallots closely—they can burn quickly!
  • Fresh herbs on top balance flavors and elevate presentation.