Cook thinly sliced squash, then mix with egg, onion mayonnaise and cheese. Top with breadcrumbs and bake.
Slice the squash thinly and then steam or simmer in some water until soft.
Mix together the egg, onion, mayonnaise, cheese, salt and pepper. Add the squash and a few Tbs of butter and mix together. Pour into a small casserole dish, top with the breadcrumbs, and dot the rest of the butter.
Bake at 350 for 30 to 40 minutes.