Cook squash in boiling salted water until slightly tender about 3-5 minutes. Drain. Saute peppers and onions in butter until soft. Combine with squash. Fold in mayo,cheese,egg,sugar. salt and pepper. Pour into a 1 1/2 quart casserole dish. Top with crushed crackers and chopped fresh parsley. Bake uncovered for 30 minutes in preheated oven at 350 degrees. note:this can be frozen after cooking.