Parboil onion in water, add oil and garlic and saute to a golden color, cool mixture. If using sausage, combine with beef and add to cooled onion mixture. Add all other ingredients and mix well.
Make cocktail size meatballs coated with flour. Heat oil in a large skillet and saute meatballs turning to evenly brown all sides. This will take approximately 10-15 minutes depending on size of meatball. Meatballs can also be baked in oven. If using oven method, place floured meatballs closely on baking sheet with sides and bake in 375 degrees F oven, turning to be sure all sides are evenly browned. This may take 20 minutes depending on size of meatball.
Meatballs can be made ahead of time and reheated for serving or they can be served at room temperature.