Mushroom Caramelized Onion Tenderloin (Ready-to-Print Version)
Tender beef with caramelized onions, mushrooms, and Gruyère delivers rich, hearty flavors and elegant comfort.
# What You’ll Need:
→ Beef
01 -
2-3 lb beef tenderloin, trimmed and butterflied
→ Fats & Oils
02 -
2 Tbsp olive oil
03 -
2 Tbsp unsalted butter
→ Vegetables
04 -
2 large onions, thinly sliced
05 -
2 cups baby bella mushrooms, finely chopped
06 -
3 cloves garlic, minced
→ Herbs & Spices
07 -
2 tsp fresh thyme
08 -
1 tsp salt
09 -
½ tsp freshly ground black pepper
→ Fillers & Seasonings
10 -
½ cup plain breadcrumbs
11 -
1 Tbsp granulated beef bouillon
→ Dairy
12 -
1 cup Gruyère cheese, freshly grated
→ Liquids
13 -
1 cup dry red wine
14 -
1 cup beef stock
# Step-by-Step Guide:
01 -
Trim silverskin and excess fat. Butterfly the tenderloin by slicing horizontally without cutting through, then open like a book. Pound gently to an even ¾-inch thickness using a meat mallet between parchment or plastic wrap. Season inside and out with half the bouillon, salt, and pepper.
02 -
Melt 1 tablespoon butter and 1 tablespoon olive oil in a large skillet over medium-low heat. Add thinly sliced onions and cook slowly, stirring regularly until golden and caramelized, about 25 to 30 minutes. Season with a pinch of salt and remove from heat.
03 -
In the same skillet, add remaining olive oil and butter. Increase heat to medium-high. Sauté chopped mushrooms until moisture evaporates and they begin to brown, around 8 to 10 minutes. Add garlic; cook 1 minute. Stir in thyme, breadcrumbs, a pinch of bouillon powder, and mix well. Combine with caramelized onions and let cool 5 to 10 minutes. Fold in grated Gruyère.
04 -
Preheat oven to 425°F (220°C). Spread mushroom and onion mixture evenly over the butterflied tenderloin, leaving a 1-inch border. Roll tightly into a log from the long edge. Secure with kitchen twine at 2-inch intervals. Pat dry and season with remaining salt, pepper, and bouillon powder.
05 -
Heat an oven-safe skillet over medium-high heat with a splash of oil. Sear the stuffed tenderloin on all sides until deeply browned, about 2 to 3 minutes per side, turning gently with tongs to prevent tearing. Remove beef and discard excess fat.
06 -
Pour red wine into the hot skillet, scraping up browned bit fond for flavor. Add beef stock and carefully nestle the stuffed tenderloin back into skillet. Transfer to preheated oven and roast for 20 to 25 minutes until the center temperature reaches 130–135°F (54–57°C) for medium-rare.
07 -
Remove from oven and transfer tenderloin to a cutting board. Tent loosely with foil and rest for 10 to 15 minutes. Simmer pan juices on stovetop to reduce slightly; adjust seasoning to taste. Slice into thick rounds and serve drizzled with pan reduction.
# Handy Tips:
01 -
Caramelize onions slowly over low heat to avoid burning and develop deep flavor.
02 -
Allow mushrooms to cook undisturbed initially to enhance browning and umami depth.
03 -
Secure the roll tightly with twine to prevent filling leakage and ensure uniform slices.
04 -
Use a probe thermometer to monitor doneness accurately for perfect medium-rare.
05 -
Resting after roasting retains juices and delivers tender, moist slices.
06 -
Deglaze with wine to incorporate fond flavors into a rich pan sauce.