Pierogi Casserole

1 pound lasagna noodles
6 cups diced and salted potatoes
8 ounces cream cheese
5 large onions
3/4 pound butter or margarine, divided

Cook noodles and potatoes. Mash potatoes and cream cheese together. Slice onions and brown in 1/4 pound butter. Add remaining butter and brown. Put small amount of butter in bottom of a 9 x 13-inch pan. Layer with noodles, potatoes, onions and butter. Cover with foil and bake at 300 degrees F for 15 minutes. Remove foil and bake an additional 10 to 15 minutes.