This hearty casserole starts with ground beef cooked in a skillet. Carrots, onions, mushrooms and garlic are added in. A sauce mixture is made of beef stock, Worcestershire sauce and seasonings. After adding peas, everything is placed in a casserole dish and prepared mashed potatoes are spread on top and baked for 5 minutes.
Start cooking the carrots and onions first; they end up too hard if they are only cooked based on the recipe instructions. After the onions and carrots soften, cook the beef. Then I add 8 oz sliced mushrooms with the garlic after the beef is browned. Set the peas on counter to thaw when beginning to cook, make sure completely thawed after 2 min of cooking or add time. The five minutes in the oven will not completely thaw the peas. You can substitute Instant mashed potatoes package for the prepared package. Follow the instructions on the package. I recommend cheese flavored, and mix with onions instead of sprinkling the onions on top.