img via: tales of thyme & place
1 can condensed cream of mushroom soup
1 c grated cheddar cheese
Wash potatoes and cut into 1/2 inch slices. Combine condensed soup, cheese, and pepper. Arrange potato slices in a sprayed casserole dish - we usually end up with three long rows of overlapping slices. Top potatoes with soup and cheese mix. Sprinkle with paprika. Bake at 350F "until cheese melts & potatoes are softened."
Edit 5/15/12: I found my mom's recipe card. This recipe is from my aunt Helen, and it bakes covered for 45 minutes, then uncovered for 10 minutes.