Preheat oven to 400°F (200°C).
Season beef tenderloin evenly with salt and black pepper.
Heat olive oil in an oven-safe skillet over high heat.
Sear the beef on all sides until well browned.
Transfer skillet to the oven and roast for 15–20 minutes.
Remove beef from skillet and let rest for 10 minutes.
In the same skillet, melt butter over medium heat.
Add minced garlic and sauté briefly until fragrant.
Pour in red wine and simmer until reduced by half.
Add beef stock, thyme, and rosemary and simmer until thickened.
Slice beef tenderloin and serve with red wine sauce.