Cook bacon in a large skillet over medium heat until crisp; remove bacon, reserving 2 teaspoons drippings in skillet. Crumble bacon, and set aside.
Sauté onion and next 4 ingredients in reserved drippings over medium-high heat until tender.
Stir together stuffing mix, seasoning packet, and milk; let stand 10 minutes. Stir in bacon, sautéed vegetables, zucchini, and egg; spoon into a lightly greased 11- x 7-inch baking dish.
Bake at 350° for 30 minutes; sprinkle with shredded cheese. Cover and bake 20 more minutes.
Note: For testing purposes only, we used Stove Top Stuffing Mix For Chicken.