Add the mushrooms. Once the vegetables and meat is tender, remove from the oven and place on the stove on high. Add the onions and mushrooms. This should thicken the sauce. If it’s thin, bring the stew to a boil on top of the stove, then lower the heat and simmer for 15 minutes. If it’s already thick, you can prepare your noodles, potatoes, or toasted bread.
