Trim squash and cut into large pieces. Drop into a large sauce pan with enough boiling water to cover. Return to a boil, reduce heat and cook until tender. Drain in a colander and then mash. In a large mixing bowl combine the squash with the eggs, the 1 cup of bread crumbs, onion, butter, sugar, salt, and black pepper. Add cheese and jalapeno pepper if desired. Turn into a 3 quart lightly greased casserole dish. Cover lightly with 1/2 cup of bread crumbs. Bake at 350 degrees until lightly browned.