Ingredients (6–8 servings):

Beef Tenderloin:

• 3–4 lb beef tenderloin, trimmed and tied

• 3 tbsp olive oil

• 4 cloves garlic, minced

• 1 tbsp fresh thyme, chopped

• 1 tbsp fresh rosemary, chopped

• 1 tbsp kosher salt

• 2 tsp freshly cracked black pepper

French Onion Au Jus:

• 3 large yellow onions, thinly sliced

• 3 tbsp butter

• 1 tbsp olive oil

• 2 cloves garlic, minced

• 1 tsp fresh thyme

• 1 tbsp balsamic vinegar (or sherry vinegar)

• 1 cup dry red wine

• 3 cups beef stock (preferably homemade or low-sodium)

• 1 tsp Worcestershire sauce

• Salt & pepper, to taste

Instructions:

1. Prepare Beef Tenderloin – Rub beef all over with olive oil, garlic, thyme, rosemary, salt, and pepper. Let rest at room temperature for 30–45 minutes.

2. Roast Beef – Preheat oven to 450°F (230°C). Place tenderloin on a rack in a roasting pan. Roast 20–25 minutes for medium-rare (internal temp ~125°F/52°C), or adjust for doneness. Rest 15 minutes before slicing.

3. Make French Onion Au Jus – While beef roasts, melt butter with olive oil in a large skillet over medium heat. Add onions and cook slowly, stirring, until deep golden brown and caramelized (25–30 minutes).

4. Add garlic and thyme, cook 1 minute more. Deglaze with balsamic vinegar, scraping browned bits. Add red wine, simmer until reduced by half. Stir in beef stock and Worcestershire; simmer 10–15 minutes until rich and flavorful. Season with salt & pepper.

5. Serve – Slice tenderloin into thick medallions. Spoon French onion au jus over and serve with sides like roasted potatoes or creamy gratin.