Season the roast with salt, pepper, and garlic powder on all sides.
Place quartered potatoes and carrot pieces in the bottom of the slow cooker, then add onion wedges.
Place the seasoned roast on top of the vegetables.
Whisk together beef broth and tomato paste, then pour over the roast and vegetables.
Add thyme and bay leaves to the slow cooker.
Cover and cook on low for 8 hours or high for 5 hours until beef and vegetables are tender.
Remove bay leaves before serving and spoon vegetables and gravy alongside sliced roast.