Peel approximately 10 medium sized potatoes. Cut into 1/8" slices.

Layer into baking dish alternating with chopped onions, salt & pepper. When baking dish is full, place margarine slices on top (approx 1/4 stick).

Mix 3 Tbs Cornstarch with 2 cups cold milk until smooth, then pour over potatoes. Add just enough milk to be able to see milk through potato slices.

Bake at 350 degrees for 1/2 hr with lid on--1 hr with lid off. Pierce potato slices with knife to see if tender before serving. Bake a bit longer if potatoes still seem tough.

Use this dish with meatloaf, baked ham, etc., since it can be baked at same time. (Serves 4-5)