Prepare the Beef Tenderloin: Trim excess fat from the beef tenderloin, leaving just enough for flavor. Pat the beef dry with paper towels.

Sear the Beef: Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Sear the beef tenderloin on all sides for 2-3 minutes each until a brown crust forms.

Layer Vegetables: Slice the onion and carrots, and mince the garlic. Once the beef is seared, transfer it to the Crockpot. Sauté the garlic in the same skillet for about 30 seconds, then add it to the Crockpot along with the onion and carrots.

Mix the Sauces: In a small bowl, combine the beef broth, soy sauce, Worcestershire sauce, and balsamic vinegar. Pour the sauce mixture over the beef and vegetables in the Crockpot.

Season: Sprinkle the beef with salt and pepper. Add fresh rosemary and thyme on top of the beef or sprinkle dried herbs over it.

Slow Cook the Beef: Cover and cook on low for 4 to 6 hours, checking the internal temperature for desired doneness (130°F for medium-rare, 140°F for medium).

Optional Gravy: If you prefer a thicker sauce, remove 1 cup of the cooking liquid, add 1 tablespoon of cornstarch mixed with 2 tablespoons of water, and bring it to a simmer until thickened.

Slice and Serve: Let the beef rest for 10 minutes, then slice against the grain into thick pieces and serve with the vegetables and sauce.