Trim all fat from roast.
Mix together flour, salt, pepper, and garlic powder in large plastic bag.
Put the roast in the bag and shake it until completely coated in flour, then brown all sides in large skillet in olive oil.
While the meat is browning, add your onion slices to the bottom of the slow cooker.
Put roast on top of onions, then pour beef broth and soup over top. (If you want to add carrots or potatoes, you could also put those on top.)
Cook 9 hours on low heat in slow cooker. Serve with mashed potatoes, veggies, and (of course!) gravy.
Remove 2 cups of the broth and place in saucepan over medium heat.
Add bouillon and stir until it's completely mixed in to the broth.
Mix together 2 tbsp. corn starch and 1/4 cup water.
Slowly add corn starch mixture into broth, stirring constantly.
Simmer over medium heat for one minute. Season if needed. (Ours didn't need any extra seasoning!)