2 lb. prepared garlic mashed potatoes
8 oz. sliced mushrooms
2 Tbsp. olive oil
1 to 1-1/2 lb. lean ground beef
1 medium onion, chopped
1 Tbsp. chopped garlic
2 Tbsp. flour
12 oz. can Heinz fat-free beef gravy or any leftover gravy
1/4 cup chopped fresh parsley