My grandmother used a version of this recipe as a way to tenderize and flavor venison. This is currently one of our family's favorite ways to eat a roast.

(Optional) Sear the beef, then sauté the onions
Place the beef, onions, peppers, and 1/2 to 1 cup of water in the crockpot on low. Cook for 8 hours (until the beef is ready to fall apart).
Once the beef is thoroughly cooked, remove it from the crockpot and shred it. Set aside. You should start your rice cooking about now.
Blend the juices and vegetable chunks together along with the flour and remaining water. I will sometimes use a blender to do this to get everything blended really well quickly, but typically I'll use an immersion blender right in the crockpot for fewer dirty dishes. However you do it, get everything thoroughly mixed and give some time for the flour to cook and the sauce to thicken. Adjust the amount of flour and water depending on how much liquid you have to start with and how thick you want the sauce to be.
Salt and pepper to taste, but this is a lot of sauce so you'll need a lot, I start with a teaspoon and go from there.
Add the shredded beef back to the sauce. Serve over rice.
15 servings