Preheat the oven to 350 degrees. Cook the noodles and set aside.
In a skillet, heat the oil. Sauté the onions until golden and place 1/2 cup of the onions aside. Make the mashed potatoes and add the onions (except the onions that have been placed aside), pepper and cheese; mixing well. Coat a 9x13 baking dish with non-stick spray. Place 3 noodles on the bottom then spread 1/3 of the potato mixture over them. Continue this process making three layers of potatoes and 4 layers of noodles. Spread the remaining 1/2 cup onions on the noodles. Cover with foil and bake for 30 minutes or until heated through.

NOTE: You can add some sliced mushrooms or even 1 cup of drained sauerkraut.