Steak Crostini with a Creamy Horseradish Sauce and Caramelized Onions

The first time I stumbled upon the delightful combination of steak crostini was during a cozy gathering at my friend Sarah’s house. The aroma of buttery shallots wafted through the kitchen, mingling with the savory, salty scent of seared steak. Oh, how that tantalizing smell danced in the air! I was immediately drawn to the little bites of heaven that came alive with each crunch of the toasted baguette, a creamy horseradish kick, and the soothing sweetness of caramelized onions. The laughter and warmth enveloped us as we savored each bite, igniting a festive flames of flavor that had everyone reaching for more.

Ever since that night, steak crostini has become a mainstay in my kitchen, loved not only for its incredible taste but also for the memories it creates. Whether it’s a cozy date night in or a lively gathering with friends, these crostini have a way of bringing people together. So roll up those sleeves and let’s create a dish that will fill your home with laughter and love!

Why You’ll Love This Recipe

  • Quick and Easy: This dish comes together in about 45 minutes, making it perfect for last-minute entertaining!
  • Flavor-Packed: Each bite bursts with the rich flavor of steak, zingy horseradish sauce, and sweet caramelized onions.
  • Crowd-Pleaser: Your guests will rave about these tender bites, and you’ll feel like a culinary superstar!
  • Customizable: Feel free to adapt the toppings or sauces to suit your personal taste.
  • Gourmet Yet Approachable: These crostini look fancy but are surprisingly easy to prepare.

Ingredients

  • 1 pound filet mignon or tenderloin: A tender cut that cooks beautifully, giving you steak that melts in your mouth.
  • Salt and black pepper (to taste): These simple seasonings enhance the flavor of the steak.
  • 2 tablespoons unsalted butter: Adds a richness to both the steak and the caramelized shallots.
  • 1 teaspoon garlic powder: A touch of garlic for that savory kick.
  • 1 teaspoon dried thyme: Adds an earthy note that complements the beef.
  • Baguette (thinly sliced): The perfect crispy vessel to hold all this deliciousness.
  • Olive oil (for brushing): A drizzle before toasting ensures a golden, crunchy topping.
  • 1/2 cup mayonnaise: The creamy base for our horseradish sauce.
  • 2 tablespoons horseradish: This zingy condiment gives your sauce a delightful kick!
  • 1 tablespoon Dijon mustard: A touch of mustard for depth of flavor.
  • 1 tablespoon lemon juice: Brightens up the sauce and balances the richness.
  • 2 large shallots (thinly sliced): Sweet and delicate, they caramelize to perfection.
  • 1 tablespoon balsamic vinegar: Adds sweetness and a bit of acidity to the shallots.
  • 1 tablespoon brown sugar: Enhance the caramelization process, giving shallots that gorgeous color.
  • Salt and black pepper (to taste): Another chance to bring all the flavors together.

Full recipe card is below.

How to Make It

Season the Steak

Start by seasoning your filet mignon or tenderloin generously with salt, black pepper, garlic powder, and dried thyme. Make sure every inch is coated in those beautiful spices! Let it rest at room temperature for at least 30 minutes. This step is crucial for getting that juicy flavor infused into the meat.

Prepare the Horseradish Sauce

In a small bowl, mix together mayonnaise, horseradish, Dijon mustard, and fresh lemon juice. Add a pinch of salt and pepper, and taste to adjust the seasoning. Trust me, you’ll want to keep this sauce on hand for all kinds of dishes! Refrigerate until ready to use. (It’s like a little jar of magic waiting to happen!)

Caramelize the Shallots

In a skillet over medium heat, melt the butter until it’s foamy and fragrant. Add sliced shallots and stir occasionally until they soften. Add balsamic vinegar, brown sugar, salt, and black pepper. Let the magic happen! Continue cooking until the shallots are gloriously caramelized and golden brown (about 30 minutes). The fragrant aroma will fill your kitchen—just wait until you taste them!

Cook the Steak

In another skillet (make sure it’s hot!), heat olive oil over medium-high heat. Cook your seasoned steak according to your desired doneness (about 4 minutes per side for medium-rare). Once perfectly cooked, remove from heat and let it rest for a few minutes—this will keep all those juicy flavors locked in!

Toast the Baguette

Preheat the oven to 375°F (190°C). Arrange the sliced baguette on a baking sheet, brush each slice with a little olive oil, and toast for about 5-7 minutes or until golden brown. The scent of warm bread will embrace you like a hug!

Assemble the Crostini

Slice the rested steak into thin strips. For assembling, spread a generous layer of the creamy horseradish sauce on each toasted bread slice, top with a slice of steak, and finish with a spoonful of caramelized shallots. Oh, how pretty they look!

Serve and Enjoy

Arrange the crostini on a lovely serving platter and garnish with fresh thyme or parsley if desired. Serve immediately, gather your friends (and maybe a glass of wine), and dive into these mouthwatering bites!

Pro Tips for Success

  • Use a meat thermometer to check for doneness (130°F for medium-rare).
  • Allow the steak to rest covered with foil for even more juiciness.
  • If you’re short on time, you can sauté the shallots on higher heat, but stir frequently to avoid burning.

Flavor Variations

  • Swap out the tenderloin for grilled chicken or pulled pork for a different twist.
  • Feel free to add some sliced jalapeños for a spicy kick!
  • Use fresh herbs like rosemary or parsley for an aromatic touch.

Serving Suggestions

These crostini would pair wonderfully with a light arugula salad drizzled with vinaigrette. A chilled glass of pinot noir or a sparkling water with lemon will keep the focus on those beautiful flavors.

Make-Ahead & Storage

You can prepare the horseradish sauce and caramelize the shallots a day in advance. Store them separately in the fridge, and assemble just before serving for the best texture!

Leftovers

Leftover crostini can be enjoyed as a light lunch. Just stack them nicely, and don’t be shy to drizzle a bit more sauce on top!

Freezing

I recommend not freezing the assembled crostini, as the bread will become soggy. However, cooked steak and caramelized onions freeze well. Just seal them in an airtight container for up to 3 months.

Reheating

To reheat, place the steak and shallots in a skillet over medium heat until warmed through. Alternatively, you can pop them in the oven for a few moments just like fresh-out-of-the-oven crostini!

FAQs

Can I use different bread?
Absolutely! Try using sourdough or a whole grain baguette for a unique twist.

What can I substitute if I don’t have horseradish?
You might try wasabi for a similar kick or a sharp mustard for a different flavor profile.

How can I make this dish gluten-free?
Use your favorite gluten-free bread or crackers! Just adjust the toppings to make sure they align.

Can I make this dish vegetarian?
Absolutely! Try grilled portobello mushrooms in place of steak and use a plant-based mayo for the sauce.

Final Thoughts

I can’t wait for you to dive into this steak crostini adventure! The melding of flavors, the aroma of caramelized shallots, and the buttery crunch of the baguette is truly unforgettable. Remember, cooking is not just about feeding our bodies; it nourishes our spirits, too. Whether you’re celebrating with a crowd or indulging in a quiet evening at home, these bites are bound to spark joy and heartwarming conversations. Happy cooking, dear friends! 🍽️💖


Feel free to refer to the full recipe card below for exact measurements and additional tips!

Steak Crostini

These bite-sized Steak Crostini are topped with creamy horseradish sauce and sweet caramelized onions, making them the perfect appetizer for gatherings.
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Course Appetizer, Snack
Cuisine American, Gourmet
Servings 4 pieces
Calories 210 kcal

Ingredients
  

For the Steak and Crostini

  • 1 pound filet mignon or tenderloin A tender cut that cooks beautifully, giving you steak that melts in your mouth.
  • to taste Salt and black pepper These simple seasonings enhance the flavor of the steak.
  • 2 tablespoons unsalted butter Adds a richness to both the steak and the caramelized shallots.
  • 1 teaspoon garlic powder A touch of garlic for that savory kick.
  • 1 teaspoon dried thyme Adds an earthy note that complements the beef.
  • 1 baguette thinly sliced The perfect crispy vessel to hold all this deliciousness.
  • for brushing Olive oil A drizzle before toasting ensures a golden, crunchy topping.

For the Horseradish Sauce

  • 1/2 cup mayonnaise The creamy base for our horseradish sauce.
  • 2 tablespoons horseradish This zingy condiment gives your sauce a delightful kick!
  • 1 tablespoon Dijon mustard A touch of mustard for depth of flavor.
  • 1 tablespoon lemon juice Brightens up the sauce and balances the richness.

For the Caramelized Shallots

  • 2 large shallots Sweet and delicate, they caramelize to perfection.
  • 1 tablespoon balsamic vinegar Adds sweetness and a bit of acidity to the shallots.
  • 1 tablespoon brown sugar Enhance the caramelization process, giving shallots that gorgeous color.
  • to taste Salt and black pepper Another chance to bring all the flavors together.

Instructions
 

Season the Steak

  • Start by seasoning your filet mignon or tenderloin generously with salt, black pepper, garlic powder, and dried thyme. Let it rest at room temperature for at least 30 minutes.

Prepare the Horseradish Sauce

  • In a small bowl, mix together mayonnaise, horseradish, Dijon mustard, and fresh lemon juice. Adjust seasoning with salt and pepper, and refrigerate until ready to use.

Caramelize the Shallots

  • In a skillet over medium heat, melt the butter and add sliced shallots. Stir occasionally and add balsamic vinegar, brown sugar, salt, and black pepper. Cook until caramelized and golden brown, about 30 minutes.

Cook the Steak

  • In another hot skillet, heat olive oil over medium-high heat. Cook the seasoned steak per desired doneness, about 4 minutes per side for medium-rare. Remove from heat and let it rest.

Toast the Baguette

  • Preheat the oven to 375°F (190°C). Arrange sliced baguette on a baking sheet, brush with olive oil, and toast for about 5-7 minutes or until golden brown.

Assemble the Crostini

  • Slice the rested steak into thin strips. Spread horseradish sauce on each toasted bread slice, top with a slice of steak, and spoon caramelized shallots on top.

Serve and Enjoy

  • Arrange crostini on a serving platter, garnish if desired, and serve immediately.

Notes

Use a meat thermometer for doneness. Assemble crostini just before serving for the best texture.
Keyword Appetizer, Caramelized Onions, Horseradish Sauce, Party Food, Steak Crostini