Preheat oven to 350°
(Cook onion in fat until golden, add meat and seasonings. Cook until browned) Note that I did this step differently: I cooked the ground beef first. Removed ground beef to drain. Wiped down skillet, then added butter and onion. Cooked until transluscent. Added ground beef back in. Added salt and pepper.
Mix in drained beans. Note that I used corn instead
Mix in soup. Add to casserole pan
Wash, peel, cute, and boil potatoes in water.
When potatoes are done (approximately 30 minutes), drain off water, add butter and milk to mash.
Mix in beat egg, and additional milk if necessary
Scoop onto top of casserole. Note that I spread the potatoes into a layer, instead of leaving into mounds.
Bake for 30 minutes