3/4 lb noodles, cooked and drained (lasagna noodles or wide egg noodles)
3/4 cup butter
3 cups instant mashed potatoes, prepared
16 slices American cheese
2 large onions, minced
Cook noodles, drain.
Melt butter and saute the onions until tender, meanwhile cook mashed potatoes according to package.
Place half of the cooked noodles in the bottom of a 13×9 casserole dish.
Layer with 8 slices of cheese, all potatoes, the remaining noodles and top with remaining 8 slices of cheese.
Poke holes through the top layer of cheese; pour butter and onion mixture over top, making sure it seeps through the holes. Serve.