Melt 4 tablespoons of butter in a medium saucepan over medium heat. Add the chopped shallots and cook them until soft and translucent, approximately 4 minutes.

Add 1⅓ cups of red wine, along with 2¼ cups of beef broth, thyme, kosher salt, and black pepper. Bring the mixture to a boil, then reduce to medium heat and simmer for 20 minutes until it reduces by half.

Rub 2 tablespoons of olive oil all over the beef tenderloin. Coat it with chopped rosemary and minced garlic, seasoning generously with salt and pepper. Let the beef sit at room temperature for 1 hour.

Preheat your oven to 425°F.

Sear the beef in a large oven-proof skillet. Heat 2 tablespoons of olive oil and 2 tablespoons of butter over medium-high heat, then add the roast. Brown it thoroughly on all sides, which should take about 7 minutes.

Roast the beef in the preheated oven until it reaches an internal temperature of 125°F for medium-rare tenderness.

Rest the roast after removing it from the skillet for 15 minutes.

Simmer any leftover bits in the skillet over medium heat. Add the remaining ¼ cup of beef broth and scrape up flavorful bits. Bring to a simmer, then mix with the reserved sauce.

Strain the sauce into a gravy boat if serving immediately.

Slice the beef tenderloin into ½-inch medallions. Serve warm with the sauce on the side.