preheat oven to 350°F. peel and chop potatoes than boil until tender. drain and mash with milk and butter.

in a skillet brown ground beef with the onion then spoon off some of the fat leaving about a tablespoon. still on the heat, season and mix in the flour. slowly add the beef stock and simmer 5 min until thickened. mix in peas (or corn) and pour into a deep casserole dish.

add large spoonfuls of the mashed potatoes then smooth them out to cover the meat making peaks. dot the top with another tbsp of butter if you want.

bake for 30 mins or until the top is beginning to brown.