Brown onion in skillet in small amount of hot fat; add beef, salt and pepper.
Cook until browned.
Drain beans; add to beef mixture with soup.
Pour into greased 2-quart casserole.
Mash potatoes; add milk and egg.
Add additional salt and pepper to taste.
Spoon in mounds over beef mixture.
Sprinkle paprika over top.
Bake at 350 degrees for 30 minutes.