Wash squash thoroughly. Place in a medium saucepan with boiling salted water to cover. Cook 25 minutes or until tender. Drain and cool slightly.
Remove and discard squash seeds. Scoop out pulp, leaving a 1/4-inch shell; chop pulp. Set aside shells and pulp.
Sauté onion, parsley, and garlic in bacon drippings until tender. Add ham; cook over medium heat 5 minutes, stirring occasionally. Add squash pulp, 1/2 cup breadcrumbs, salt, pepper, and hot sauce; cook 10 minutes. Remove from heat, and stir in egg.
Spoon stuffing mixture into squash shells. Place stuffed squash in a shallow baking dish; sprinkle with remaining breadcrumbs. Bake at 375° for 15 minutes or until breadcrumbs are lightly toasted.