The luscious Swiss Cheese Cream Sauce takes a few extra minutes to make, but the rich results are worth the effort. Greg makes this casserole up to a day ahead of the party or freezes it earlier in the week.
2 tablespoons butter or margarine
3 pounds yellow squash, thinly sliced
1 small onion, chopped
1 1/4 teaspoons salt
1/2 teaspoon pepper
2 (8-ounce) cans sliced or chopped water chestnuts, drained