Place the stew meat in a large mixing bowl. Season with salt and black pepper, then toss to coat.
Heat the olive oil in a large skillet over medium-high heat.
Add the beef in a single layer and sear for about 3 minutes per side, or until browned. Work in batches to avoid overcrowding the skillet.
Transfer the seared beef to the bottom of a 6-quart crockpot.
Sprinkle the gravy mix over the beef. Add the diced onion and minced garlic.
Whisk the beef broth and cornstarch together in a bowl until the cornstarch is completely dissolved.
Stir in the cream of mushroom soup and Worcestershire sauce. Pour the mixture over the beef.
Add the dried thyme and bay leaf. Gently stir to coat the beef.
Cover and cook on LOW for 7 to 8 hours, or until the beef is tender and can be easily cut with a fork.
Remove and discard the bay leaf. Stir the gravy, then serve the beef tips over mashed potatoes, rice, or egg noodles. Garnish with fresh herbs if desired.