This is the recipe i got from my mom-mom c. she makes the best squash casserole i have ever eaten in my entire life . she makes it every year at Christmas time for us and lets just say we usually fight in a good way for whats ever left over which isn't very much because its just that darn good its just chock full of yummy goodness that you will fine your self going back for then one helping .. enjoy :)
Steam squash and onion together until tender drain and mash .
Add soup, sour cream and drained , sliced water chesnuts and mix well .
Melt butter or margarine and toss with dressing mix put about 2/3 of the buttered mix in bottom of 2-qt casserole dish. Pour in the squash mixture and top with the remaining crumbs. Bake for 25 minuted at 350 degrees ... enjoy:)