Saute 1 onion in 1/4 cup margarine until translucent. Add 4-6 cups leftover potatoes and 1/2-3/4 can corn beef. Season to taste with salt and pepper. Cook until heated through.
Note: This would be super with corn beef that does not come from a can, as well. In fact, my husband used to make it any time we had a little roast beef left over.
