Roasted Beef Tenderloin with Caramelized French Onions and Horseradish Sauce

Roasted Beef Tenderloin with French Onions and Horseradish Sauce is a show-stopping dish made for special meals and celebrations.

introduction — Roasted Beef Tenderloin with French Onions and Horseradish Sauce

This Roasted Beef Tenderloin with French Onions and Horseradish Sauce article gives clear steps and tips so you can cook with confidence.
This recipe is rich, simple, and elegant, and it pairs well with many sides for a full meal.
For more ideas on quick dinners that pair with roast beef, see this 30-minute dinner ideas to round out the menu.

why make Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Make this Roasted Beef Tenderloin with French Onions and Horseradish Sauce for holidays, birthdays, or any time you want to impress guests.
The beef is tender and classic, the onions add sweet depth, and the horseradish sauce brings bright heat.
It looks fancy but is simple to follow, so you get great results without stress.

how to make Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Follow simple, clear steps to make this Roasted Beef Tenderloin with French Onions and Horseradish Sauce.
Start the onions first, then make the sauce, and finally roast the beef so everything is ready to serve together.

• Make the French onions, and keep them warm.
• Whisk the horseradish sauce, chill it.
• Season and roast the beef, then rest and slice.

For another beef idea that uses similar techniques, check this apple cider braised beef recipe.

Ingredients — Roasted Beef Tenderloin with French Onions and Horseradish Sauce

For the French Onions:

• Olive oil, as needed
• 3 tablespoons butter
• 2 1/2 lbs thinly sliced onions
• Kosher salt, to taste
• Freshly cracked black pepper, to taste
• 2 large fresh thyme sprigs
• 2 large fresh rosemary sprigs
• 1 bay leaf
• 1/4 cup sherry wine

For the Horseradish Sauce:

• 6 oz mayonnaise
• 6 oz sour cream
• 3 oz prepared horseradish
• 1/2 lemon, zested and juiced

For the Roasted Beef Tenderloin:

• 3 lbs trimmed whole beef tenderloin
• Olive oil, as needed
• 1 tablespoon kosher salt
• 1 tablespoon granulated garlic
• 2 teaspoons freshly cracked black pepper
• Fresh thyme leaves, to garnish

Directions — Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Step 1: Make the French Onions

• Heat a large pot over medium-high and add oil to coat the bottom and the butter.
• Add sliced onions, a big pinch of salt and cracked pepper, and cook for about 10 minutes, stirring often.
• Lower heat to medium-low, add thyme, rosemary, and bay leaf, and cook slowly until onions are caramelized, about 45 minutes, stirring now and then.
• Stir in sherry and simmer about 15 minutes. Remove herb sprigs and bay leaf. Adjust salt and keep warm.

Step 2: Make the Horseradish Sauce

• Combine mayonnaise, sour cream, horseradish, lemon zest, and lemon juice in a bowl.
• Whisk until smooth. Season with salt and pepper.
• Chill the sauce until serving.

Step 3: Prepare and Roast the Beef Tenderloin

• Preheat oven to 450°F (230°C). Place the beef on a rack on a sheet pan. Pat dry and let sit 20 minutes at room temperature.
• Drizzle with olive oil and rub to coat. Mix salt, granulated garlic, and black pepper and rub over beef.
• Roast about 30 minutes, until internal temp reaches 135°F for medium-rare.
• Remove and tent with foil. Rest 15 minutes.

Step 4: Slice and Serve

• Slice into 1/4-inch pieces. Serve with French onions and horseradish sauce. Garnish with thyme.

how to serve Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Serve Roasted Beef Tenderloin with French Onions and Horseradish Sauce warm on a large platter.
Place a mound of French onions beside the sliced beef and spoon horseradish sauce in a small bowl for guests.
Add simple sides like roasted potatoes or a green salad to balance the plate.

how to store Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Store any leftover Roasted Beef Tenderloin with French Onions and Horseradish Sauce in airtight containers.
Keep the beef and onions refrigerated up to 3 days, and the sauce for up to 4 days.
Reheat beef gently in a low oven or slice cold for sandwiches.

tips to make Roasted Beef Tenderloin with French Onions and Horseradish Sauce

• Use a meat thermometer to check doneness so you do not overcook the tenderloin.
• Let the beef rest before slicing to keep it juicy.
• Caramelize onions slowly for the best sweet flavor.

If you need quick meal ideas to serve with the roast, try this collection of simple recipes for sides and salads.

variation (if any) — Roasted Beef Tenderloin with French Onions and Horseradish Sauce

• Swap sherry for red wine or beef broth in the onions for a different taste.
• Mix fresh herbs into the horseradish sauce for extra brightness.
• For a pepper crust, add more cracked pepper to the beef rub.

FAQs — Roasted Beef Tenderloin with French Onions and Horseradish Sauce

Q: What internal temperature is best for medium-rare roast beef?
A: Aim for 135°F (57°C) before resting, which finishes to medium-rare after resting.

Q: Can I make the French onions ahead of time?
A: Yes. Make the onions a day ahead and reheat gently on the stove before serving.

Q: What kitchen tool helps cook the beef perfectly?
A: A good instant-read meat thermometer makes it easy to get the right doneness. Buy it here

Q: Can I use a different cut of beef?
A: You can, but cooking time and method will change. Tenderloin is best for very tender slices.

Q: Is the horseradish sauce spicy for everyone?
A: The sauce has a bite from horseradish. Adjust the amount to suit your taste.

Roasted Beef Tenderloin with French Onions and Horseradish Sauce

A show-stopping dish perfect for special meals, this roasted beef tenderloin is paired with sweet French onions and a zesty horseradish sauce for a delightful balance of flavors.

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Prep Time 1 hour hr 15 minutes mins

Cook Time 1 hour hr

Total Time 2 hours hrs 15 minutes mins

Course Dinner, Main Course

Cuisine American

Servings 8 servings

Calories 500 kcal

Ingredients

  

For the French Onions

• Olive oil, as needed For coating the pot
• 3 tablespoons butter
• 2 1/2 lbs thinly sliced onions
• Kosher salt, to taste
• Freshly cracked black pepper, to taste
• 2 large fresh thyme sprigs
• 2 large fresh rosemary sprigs
• 1/4 cup sherry wine

For the Horseradish Sauce

• 6 oz mayonnaise
• 6 oz sour cream
• 3 oz prepared horseradish
• 1/2 lemon zested and juiced

For the Roasted Beef Tenderloin

• 3 lbs trimmed whole beef tenderloin
• Olive oil, as needed For coating the beef
• 1 tablespoon kosher salt
• 1 tablespoon granulated garlic
• 2 teaspoons freshly cracked black pepper
• Fresh thyme leaves, to garnish

Instructions

 

Make the French Onions

• Heat a large pot over medium-high and add oil to coat the bottom and the butter.
• Add sliced onions, a big pinch of salt and cracked pepper, and cook for about 10 minutes, stirring often.
• Lower heat to medium-low, add thyme, rosemary, and bay leaf, and cook slowly until onions are caramelized, about 45 minutes, stirring now and then.
• Stir in sherry and simmer about 15 minutes. Remove herb sprigs and bay leaf. Adjust salt and keep warm.

Make the Horseradish Sauce

• Combine mayonnaise, sour cream, horseradish, lemon zest, and lemon juice in a bowl.
• Whisk until smooth. Season with salt and pepper.
• Chill the sauce until serving.

Prepare and Roast the Beef Tenderloin

• Preheat oven to 450°F (230°C). Place the beef on a rack on a sheet pan. Pat dry and let sit 20 minutes at room temperature.
• Drizzle with olive oil and rub to coat. Mix salt, granulated garlic, and black pepper and rub over beef.
• Roast about 30 minutes, until internal temp reaches 135°F for medium-rare.
• Remove and tent with foil. Rest 15 minutes.

Slice and Serve

• Slice into 1/4-inch pieces. Serve with French onions and horseradish sauce. Garnish with thyme.

Notes

Use a meat thermometer to check doneness so you do not overcook the tenderloin. Let the beef rest before slicing to keep it juicy. Caramelize onions slowly for the best sweet flavor.

Keyword Beef Recipe, French Onions, Horseradish Sauce, Roasted Beef Tenderloin, Special Occasion Recipe