Mix beef, pork, and veal together in a bowl with the onions, egg, white bread broken up into small pieces, and sprinkling of salt and pepper.
Roll into balls about the size of a golf ball or a little smaller.
Saute meatballs in melted margarine and the oil until browned.
Remove meatballs from the pan and set aside.
Add flour to the grease in the pan(to make a roux) and stir constantly for 30-60 seconds.
Add 1/2 of the carton of half and half, the gravy master, and salt and pepper to taste.
Stir until it starts to thicken, and then add meatballs back to the pan.
Simmer on low for 40 minutes.
As it thickens more, you can add the rest of the half and half as needed. (I usually end up adding the rest little by little because I like it saucey and because some of the sauce cooks away while simmering.).
Re-season with salt and pepper to your taste, before serving on top of cooked egg noodles. Enjoy!