Cook lasagna noodles and drain.
Line bottom of 9x13 pan with a single layer of noodles.
In bowl mix mashed potatoes, cheese, egg, and spices.
Spread half over noodles.
Cover with another layer of noodles, then potato mixture.
Melt butter or margarine in fry pan, saute onion until clear and soft.
Pour over noodles.
Cover with foil.
Bake 30 minutes in 350F oven.
Let stand 10 minutes before cutting.
Serve with sour cream.
