In large bowl, whisk together egg and milk. Tear bread slices into bite sized pieces and add to bowl. Stir to coat and let sit 10 minutes. Add ground chuck, garlic, pepper, salt, and cayenne. Make meatballs (I came out with 28).
Place on a cookie sheet sprayed with cooking spray. Cook at 325 F for about 10 minutes. Turn once. Cook an additional 10 minutes. Drain.
Combine every other ingredient except green onions. Add to a pan and cook until thickened stirring constantly. Pour over meatballs. Add chopped green onions.
The original recipe called for frying the meatballs, but I like baking them instead and draining off the grease. Use whichever method you prefer.