Saute the onion in a bit of oil over medium heat until tender, and add to the ground meat in a large bowl. Add the bread crumbs, salt, mustard, chili powder mustard and eggs.
Brown the meatballs in a large skillet or casserole dish. Remove and set aside.
In the casserole, stir the rest of the flour into the drippings. Cook lightly to remove flour taste, then add remaining wine, tomato sauce, water and pepper. Cook until thickened, stirring as needed.
put the meatballs and the vegetables in the casserole pot, sitrring to v=cover with the gravy mix. Cover with oven proof lid.
Bake 350F for about 45 minutes - 1 hour until veggies are tendered.
To make this a one pot dish, use a heavy metal or cast iron dutch oven, large skillet, or casserole dish. Otherwise you'll need to use a large skillet on the stove top and then put everything into an oven proof casserole dish for the final baking.