Mama Leone's Bolognese Sauce

This recipe came from one of the first cookbooks in my collection. As a matter
of fact, I can't even locate the book now. Chances are it got lost in the shuffle
of too many transatlantic moves over the years. As I recall the title was  simply
"Mama Leone's Italian Cookbook." In any case, it is out of print now, but the family legend lives on...

Leone's Italian Cookbook
Gene Leone, 1997, Buccaneer Books

1/4 cup olive oil
1/4 cup fresh sweet butter
2 ounces salt pork, diced
1/4 pound onions, peeled and diced
1/2 pound Italian sweet sausage
1/2 pound lean ground beef
4 chicken livers, chopped fine
2 garlic cloves, pressed
1/2 teaspoon fresh rosemary
1 bay leaf
1/4 teaspoon freshly ground black pepper
6 tablespoons dry white wine
1 cup canned plum tomatoes, sieved
2 medium ripe tomatoes, chopped
1 cup boiling water

Combine olive oil, butter and salt pork in saucepan; heat. Add onions and brown slowly. Remove sausage from casing and cut meat into ½-inch pieces. Add to onions with beef and chicken livers. Brown slowly 15 minutes. Chop garlic with rosemary and add to sauce with bay leaf and pepper. Stir well and cook 10 minutes. Add wine; stir, cover and cook 10 minutes. Remove sausage and chop fine. Place back in sauce. Add sieved and chopped tomatoes. Remove and discard bay leaf. Add boiling water and cook slowly, uncovered, 40 minutes. Makes about 4 cups.