Cut stewing beef in 1 1/2 inch cubes. Season the meat with salt and pepper.
In a large saucepan or stew pot, heat the Canola oil over medium heat. Add the onion, garlic, bell pepper, and carrots. Saute until the onions are translucent. Add the meat and continue to cook, stirring often, until it is browned on all sides. Add the peanut butter and broth mixture, tomatoes and liquid, thyme, and bay leaf.
Stir well and bring to a boil. Reduce heat to low and simmer, stirring often for about 1 1/2 hour or until the meat is tender. Taste and add salt and pepper if desired. Remove the bay leaf and discard.
Serve hot over rice.
Cook on Low for 7 hours if using your slow cooker.