1. Add all ingredients to a large bowl and mix with hands until evenly distributed.
2. Roll into about 12 meatballs.
3. Cook in large oiled frypan, turning frequently until brown.
4. Remove meatballs to ovenproof serving dish.
5. Add sauce to pan and stir to scrape up bits of meat.
6. Pour sauce over meatballs and top with mozzarella cheese. Melt briefly under broiler.

Sauce:

7. Brown bacon till crisp, reserve bacon bits.
8. Process mushrooms and onions in food processor (about 4 pulses), add to the bacon fat and cook 6-10 min.
9. Add garlic and anchovies and cook until the anchovies dissolve about 3 min.
10. Add tomatoes and wine, bring to a boil. Cook 30 min
11. Stir in cheese, basil and tomato paste and cook 10 min.