Roasted Beef Tenderloin with French Onions and Horseradish Sauce

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A beautifully roasted beef tenderloin is the crown jewel of any holiday dinner table, and when paired with sweet, caramelized French onions and a punchy horseradish cream sauce, it turns into something utterly unforgettable. This dish is all about balance—tender, juicy beef meets savory onions and a creamy, spicy finish. Whether you’re hosting a celebratory dinner or simply treating your loved ones to a gourmet experience at home, this recipe promises to impress.

What makes this roasted beef tenderloin so special is how each component complements the other. The beef is seared for a flavorful crust, roasted to perfect doneness, and served alongside slow-cooked onions that melt in your mouth. Then comes the horseradish sauce, bringing just the right amount of heat to cut through the richness. The result is a harmonious dish that tastes as elegant as it looks.

Why You’ll Love This Roasted Beef Tenderloin with French Onions and Horseradish Sauce

This dish is a showstopper without being complicated. The tenderloin is incredibly easy to prepare, yet delivers restaurant-quality results. The slow-cooked onions add a deeply savory-sweet layer that brings warmth and nostalgia to every bite. And the horseradish sauce? It ties everything together with a creamy, sharp kick.

You’ll love how it feels both classic and fresh. It’s perfect for special occasions, yet approachable enough to make for a weekend family dinner. Plus, you can make most of it ahead of time.

What Cut of Beef Should I Use for the Tenderloin?

For the best results, go with a center-cut beef tenderloin. It’s uniform in shape, making it easier to cook evenly and slice beautifully. You can ask your butcher to trim it for you, removing the silver skin and excess fat. If you’re buying a whole tenderloin, plan to tie it with kitchen twine for even roasting.

The key is quality—since this dish is all about letting the beef shine, choose a prime or high-grade cut if your budget allows. The tenderness of this cut makes it ideal for roasting and serving medium-rare to medium, where it maintains juiciness and rich flavor.

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

This recipe uses simple ingredients that come together for an elegant and bold dish. Each one plays a crucial role in building flavor and texture:

• Beef Tenderloin (center-cut): The star of the show—tender, buttery, and ideal for roasting.
• Kosher Salt and Black Pepper: Seasoning the beef generously helps form that savory crust.
• Olive Oil: Used for searing the tenderloin to lock in moisture.
• Butter: Essential for basting and adding richness to the beef and onions.
• Yellow Onions: Slowly caramelized to bring out their natural sweetness and depth.
• Fresh Thyme: Adds earthy aroma and complexity to the dish.
• Garlic: Sautéed with the onions for another layer of savory flavor.
• Prepared Horseradish: The spicy backbone of the creamy sauce.
• Sour Cream: Base of the sauce, giving it tang and smoothness.
• Mayonnaise: Adds body and creaminess to the horseradish sauce.
• Chives or Parsley: For garnish and a fresh, herbal note to finish.

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

Step 1: Sear the Tenderloin

Pat the beef dry and season generously with salt and pepper. In a heavy skillet over high heat, sear the tenderloin on all sides in olive oil until a deep brown crust forms.

Step 2: Roast the Beef

Transfer the seared tenderloin to a preheated oven (around 425°F). Roast until it reaches your desired internal temperature, about 20-25 minutes for medium-rare. Let it rest at least 10 minutes before slicing.

Step 3: Caramelize the Onions

In a large skillet, melt butter and add sliced onions with a pinch of salt. Cook on medium-low heat, stirring occasionally, until deeply golden and caramelized—this can take 25-30 minutes. Add garlic and thyme during the final few minutes.

Step 4: Make the Horseradish Sauce

In a small bowl, mix sour cream, mayonnaise, and prepared horseradish. Add a pinch of salt and pepper to taste. Stir in fresh chives or parsley. Chill until ready to serve.

Step 5: Assemble and Serve

Slice the rested tenderloin, spoon caramelized onions over and around the beef, and drizzle generously with horseradish sauce. Garnish with fresh herbs for a restaurant-worthy presentation.

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How to Serve and Store Roasted Beef Tenderloin with French Onions and Horseradish Sauce

This stunning dish serves 6 to 8 people, making it ideal for holiday dinners or weekend gatherings. Present the sliced tenderloin on a large platter with the caramelized onions nestled around and a drizzle of horseradish sauce on top. Serve additional sauce on the side for guests who want extra zing.

Leftovers can be stored in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or enjoy thin slices cold in sandwiches. Store the horseradish sauce separately to preserve its creamy texture.

What to Serve With Roasted Beef Tenderloin?

H3: Garlic Mashed Potatoes

Creamy and buttery, they pair perfectly with the savory beef and horseradish sauce.

H3: Roasted Brussels Sprouts

Their earthy crispness balances the richness of the tenderloin beautifully.

H3: Red Wine Glazed Carrots

Adds sweetness and a hint of acidity that complements the entire dish.

H3: Creamed Spinach

Silky and indulgent, it makes for a comforting side.

H3: Yorkshire Pudding

An old-school pairing that soaks up every drop of sauce.

H3: Mixed Green Salad with Balsamic Dressing

Bright, fresh greens to lighten up the plate.

H3: Herb Butter Dinner Rolls

Perfect for sopping up caramelized onions and horseradish sauce.

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Frequently Asked Questions

Can I prepare the tenderloin ahead of time?
Yes! You can sear the tenderloin a few hours ahead and refrigerate it. Let it come to room temperature before roasting. The horseradish sauce can also be made a day in advance.

What if I don’t like horseradish?
You can replace it with Dijon mustard for a milder, tangy sauce that still complements the beef wonderfully.

How do I know when the beef is done?
Use a meat thermometer. For medium-rare, remove the beef at 125-130°F. It will rise a few degrees as it rests.

Can I use another cut of beef?
Yes, a sirloin roast or ribeye roast can work, but keep in mind they may require slightly different cooking times and won’t be quite as tender as filet.

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Conclusion

Roasted Beef Tenderloin with French Onions and Horseradish Sauce is a dish that brings elegance, comfort, and incredible flavor to your table. It’s the kind of meal that turns an ordinary evening into something special. With a few quality ingredients and a little technique, you’ll have a show-stopping centerpiece that’s sure to earn applause. Serve it for holidays, anniversaries, or simply when you want to treat the people you love.

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