Roasted Beef Tenderloin with French Onions and Horseradish Sauce

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This roasted beef tenderloin is the definition of holiday-worthy luxury. The tenderloin is seared to perfection, roasted until it melts like butter, and paired with deeply caramelized French onions that bring a savory-sweet complexity. Add a creamy horseradish sauce with just the right amount of heat, and you’ve got an unforgettable main course that delivers on elegance and bold flavor.

Whether you’re serving this for a Christmas dinner, a special birthday, or a date night feast at home, it’s the kind of meal that feels like a celebration. With just a handful of thoughtful ingredients and smart techniques, this beef tenderloin will be your go-to when you want to impress without overcomplicating the process.

Why You’ll Love This Roasted Beef Tenderloin

This recipe is more than just a roast—it’s an experience. The beef tenderloin is incredibly tender and juicy, with a crust that locks in all the flavor. The French onions take their time to caramelize, bringing a rich umami sweetness that plays beautifully with the bold, creamy horseradish sauce. Best of all, this dish looks and tastes like it came from a fine dining restaurant, but it’s completely achievable in a home kitchen.

What Cut of Beef Should I Use for Tenderloin?

You want to use center-cut beef tenderloin, also known as chateaubriand. This section of the tenderloin is uniform in shape, which means it cooks evenly and slices beautifully. Look for a piece that has been trimmed of silver skin and excess fat, or ask your butcher to do it for you. A 2- to 3-pound piece is perfect for feeding a small gathering with elegance and ease.

Ingredients for the Roasted Beef Tenderloin with French Onions and Horseradish Sauce

For a dish this decadent, the ingredients are refreshingly simple. Each one has a clear purpose, and together they create a harmony of texture and flavor.

• Beef tenderloin
• Yellow onions
• Butter
• Olive oil
• Fresh thyme
• Garlic cloves
• Kosher salt
• Black pepper
• Sour cream
• Prepared horseradish
• Dijon mustard
• White wine vinegar

The beef tenderloin is the star—tender and rich with a buttery texture. Yellow onions are slowly caramelized into sweet, jammy perfection. Butter and olive oil bring richness and help achieve a deep golden crust. Fresh thyme and garlic infuse the roast with aromatic depth. Salt and pepper are essential for enhancing all the flavors.

In the horseradish sauce, sour cream provides the creamy base, prepared horseradish adds punch, Dijon mustard gives a tangy sharpness, and white wine vinegar ties everything together with brightness.

How To Make the Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Step 1: Sear the Beef

Start by patting the beef dry and seasoning it generously with salt and pepper. In a hot skillet with olive oil, sear the tenderloin on all sides until it’s browned and crusty. This locks in juices and adds flavor.

Step 2: Roast the Beef

Transfer the seared beef to a preheated 425°F oven. Roast for 20-25 minutes or until the internal temperature reaches 125°F for medium-rare. Let it rest for at least 15 minutes before slicing.

Step 3: Caramelize the Onions

While the beef roasts, slice the yellow onions and cook them low and slow in butter with a touch of salt. Stir frequently, allowing them to turn deep golden brown over about 30-40 minutes. Add garlic and thyme toward the end for added depth.

Step 4: Make the Horseradish Sauce

In a bowl, mix together sour cream, prepared horseradish, Dijon mustard, white wine vinegar, salt, and pepper. Adjust the heat level to taste and chill the sauce until serving.

Step 5: Assemble and Serve

Slice the rested tenderloin into thick medallions. Spoon over some of the caramelized onions, and serve with a generous dollop of the horseradish sauce on the side. Garnish with a sprig of thyme or freshly cracked pepper if desired.

How to Serve and Store Roasted Beef Tenderloin

This dish is hearty enough to be the centerpiece of your holiday or special dinner spread. It comfortably serves 6 to 8 people, especially when paired with sides. For presentation, serve the sliced tenderloin over a bed of French onions, with the horseradish sauce in a small bowl so guests can serve themselves.

Leftovers should be stored in an airtight container in the fridge for up to 3 days. Reheat gently in a low oven or enjoy the beef cold in sandwiches with extra sauce and onions—it’s fantastic either way.

What to Serve With Roasted Beef Tenderloin?

Creamy Mashed Potatoes

The buttery richness of mashed potatoes pairs perfectly with the tenderloin and helps soak up those sweet onions and sauce.

Garlic Green Beans

Crisp-tender green beans sautéed with garlic add a bright and fresh contrast.

Roasted Asparagus

A classic side that adds texture and color to the plate.

Yorkshire Pudding

This traditional English favorite adds an irresistible, airy bite to soak up the juices.

Baked Mac and Cheese

Creamy and comforting, this indulgent side plays nicely with the bold horseradish sauce.

Herb Cheese Quick Bread

Soft, savory bread is always a good idea next to beef and onions. Especially warm out of the oven.

Zesty Lemon Basil Pasta Salad

A chilled pasta salad brings a refreshing citrus lift that balances the richness of the dish.

Want More Beef Dinner Ideas?

If you love this roasted beef tenderloin, you’ll definitely want to try some of these beefy comfort meals next:

• Creamy Beef and Shells Recipe
• Stovetop Creamy Ground Beef Pasta
• Cheesesteak Tortellini in Rich Provolone Sauce
• Creamy Ground Beef Alfredo Pasta
• Cheesy Baked Tortellini with Meat Sauce

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Let me know in the comments how your roast turned out. Did you go heavy on the horseradish or dial it down? Did the onions steal the show? I’d love to hear how you made this one your own.

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