how long to cook roast in slow cooker
1 Pour onion and mushroom mixture over the top of the roast. 2  Cover slow cooker, turn to high and cook the roast for 5-6 hours, until the meat is fork tender. 3  Skim off any fat from the surface and remove the bones. 4  Season with salt and pepper to taste. Stir in onion; cook for 5 minutes, until onions are translucent and begin to brown. 2  Add garlic, stir for about a minute. 3  Stir in 1 1/2 tablespoons flour; cook and stir for about 1 minute.