Melt butter in saucepan. Add 1/2 onion coarsely chopped and cook till almost tender. Then add mushrooms and garlic on medium heat. Then add diced tomatoes and sauce. Let simmer on LOW HEAT.
In large pan bring 3 quarts water to a boil. In a large bowl add sausage, parmesan, and other half onion finely chopped and mix well. Roll mix into about 3/4 inch balls and add to skillet -- then brown turning often. Once browned, add 1/4 cup red cooking wine and cook until wine disappears turning meatballs continually.
Add spaghetti to boiling water and salt to taste. Plate spaghetti. Add sauce. Add meatballs on the side.