Just grab a square casserole dish and follow these easy steps. Spread one half of the potato mixture on bottom of 13 x 9 casserole dish. The recipe states to use 5 potatoes without mentioning what size and one onion without saying large onion or small. How to Make Ham and Potato Casserole. If I had used large potatoes then the casserole would never have fit into the baking dish. Top the layer with ham. Mix until everything is combined. Spread remaining potato mixture over the ham. The recipe would be easier to follow if the size of the potatoes had been given. Making this casserole is as easy as it gets! Bake â¦ 6 medium potato, peeled and thinly sliced (about 6 cups) 1 medium onion, chopped (about 1/2 cup) 2 cans (10 1/2 ounces) Campbellâs® Condensed Cream of Mushroom Soup or 98% Fat Free Cream of Mushroom Soup 2/3 cup water Sprinkle on 1/3 of the ham/onion mixture, then 1/3 of the cheese, then pour on 1/3 of the cream mixture. Using a mandoline or slicer, slice potatoes into 1/8-inch slices (very thin.) https://www.yummly.com/recipes/cheesy-potato-casserole-with-ham Melt butter in microwave in large bowl. Layer 1/3 of the potato slices in the buttered casserole dish. Mix in condensed soup, sour cream, and cheese. Grab a large bowl and toss in your ham, some frozen potatoes, shredded cheese, cream of chicken soup, and some sour cream. Pour in potatoes, coat well.