Pierogi Lasagna

This recipe was contributed by my friend Mandy.

1 lb. lasagna noodles
4 lbs red or white potatoes (I use Ore-Ida steam and mash)
1/4 c sour cream (optional)
1/2 c milk
2 c shredded cheese or velveeta
3/4 c butter (1.5 sticks)
1 onion, sliced in rings

Cook the noodles. Cook the potatoes and mash them and then add in the optional sour cream and milk, mix some more. Add salt to taste. Stir in cheddar.
Melt all the butter over medium-high heat. Then sautee onions until the rings no longer hold their shape.
Preheat over to 375. Grease the bottom of a 9x13 baking dish with some of the onion butter. Lay noodles on the bottom of the dish, then spread the potatoes, a dollop at a time, along the length of each noodle. Once done, smooth the potatoes, then spread about a quarter of the onion on top, and drizzle a small amount of butter as well. Repeat this twice (or more if your dish can accommodate), then top with noodles and the remainder of the onions and butter.
Cook about 45 minutes, or until the top is browned and bubbling.