In a small bowl, mix together the olive oil, kosher salt, black pepper, minced garlic, rosemary, thyme, Dijon mustard, and balsamic vinegar to create a marinade.
Place the beef tenderloin on a cutting board and pat it dry with paper towels. Rub the marinade all over the beef, ensuring it is evenly coated. Let it sit at room temperature for about 30 minutes.
In a large oven-safe skillet or roasting pan, heat a little olive oil over medium-high heat. Sear the beef tenderloin on all sides until browned, about 2-3 minutes per side.
Transfer the skillet or roasting pan to the preheated oven. Roast the beef for about 25-35 minutes, or until it reaches your desired level of doneness (135°F for medium-rare, 145°F for medium).
Once done, remove the beef from the oven and let it rest for at least 10-15 minutes before slicing.
Slice the beef tenderloin into 1-inch thick slices and serve warm.
Notes
For a more flavorful crust, consider adding a tablespoon of freshly cracked black pepper to the marinade.
For a different flavor profile, try substituting the rosemary and thyme with fresh parsley and oregano.