Best Squash Casserole Ever

2 lbs squash
I large carrot grated
1 large onion minced
1 Pepperidge Farm stuffing mix
½ pint sour cream
1 can cream of mushroom soup
1 stick butter
salt and pepper to taste

Cook squash in salted water till soft. Drain and mash with butter. Add other ingredients, reserving half the package of stuffing for the top of the casserole. Bake at 350 for 30 – 40 minutes.
JD