10 to 12 medium to large potatoes
3 medium onions
1 can cream of mushroom soup or 1 can cream of chicken soup
1 small jar sliced mushrooms (optional)
4 large tbsp. mayonnaise
4 large tbsp. Cheez Whiz or 1 (15 oz.) can Elrio cheese sauce with jalapeno (mild) pepper

Peel and cut in half potatoes; boil for 25 minutes. Let them cool after cooking. Chop up onions and microwave for 10 to 12 minutes (keep covered while in microwave). Cut up potatoes in chunks and let cool. Mix soup, mayonnaise, onions, sliced mushrooms and Cheez Whiz first. Then add cooled chunks of potatoes and mix all together. In a 10-inch Corning Ware bowl, spray with Pam or butter spray. Put everything into bowl and sprinkle over top with 100% Parmesan cheese. Preheat oven to 350°F. Cook for 55 minutes.