Pam's Favorite Sour Cream Squash Casserole

2- 16oz. cans of yellow canned squash

1 cup of sour cream

1 cup of Parmesan

1/2 cup mayo

1 cup chopped onions

1 stick butter

1 roll of Ritz crackers

1 cup shredded cheddar

Drain squash and mash it up with a fork. Add sour cream, Parmesan, cheddar cheese, mayo, onions and stir together. Melt butter and crumble Ritz crackers in a bowl. Spread mixture on top of squash. Bake at 350 degrees until hot and bubbly.