Tomato-Braised Meatballs with Melting Mozzarella

I feel like I've made a lot of variations on meatballs lately. Some with Indian flavours, some rich and meaty. Do I really need another meatball recipe? If it's one with melted mozzarella hiding inside then the answer is a resounding yes! I served this to a few dinner guests and was met with great approval. Even better for party planning, the meatballs themselves can be made a day in advance. I didn't have pecorino romano on hand, so I just used a good quality parmesan.

Tomato-Braised Meatballs with Melting Mozzarella (from The Cheesemonger's Kitchen)

Ingredients
Meatballs
225 stale baguette, sliced
1/2 cup (30g) fresh basil, chopped
450g ground beef
450g ground pork
1 cup (100g) grated pecorino romano cheese
2 eggs, beaten
1 tsp salt
pepper
20 bocconcini di mozzarella cheese
Sauce
6 tbsp olive oil
2 small onions, minced
3 garlic cloves, peeled
910g fresh or canned San Marzano or plum tomatoes, peeled, seeded, and chopped (I used a 798mL can of whole tomatoes)
salt and pepper
pinch of crushed red chilies
Assembly
1/4 cup olive oil
1/2 cup water

1. Submerge bread in enough cold water to thoroughly soak and then squeeze dry. Tear into small pieces and place in large mixing bowl.
2. Add basil, beef, pork, pecorino, eggs, salt, and a few grindings of pepper to bowl. Mix.
3. Form mixture into 20 patties 2" in diameter. Lay a bocconcini ball on each patty and mold meat mixture around to form meatballs.
4. Heat olive oil in large saucepan over low heat. Add onions and cook 10 minutes or until translucent.
5. Turn up heat to medium, add garlic, and cook for 3 - 4 minutes or until aromatic.
6. Add tomatoes, season well with salt and pepper and add chilies.
7. Simmer sauce for 20 minutes, stirring often. Puree with immersion blender.
8. In a deep saucepan large enough to hold meatballs and sauce, heat olive oil until hot. Brown meatballs a few at a time.
9. Deglaze bottom of pan with water, scraping to release bits of meat.
10. Add tomato sauce and then meatballs. Bring to simmer and cook for 10 minutes or until cooked through. Serve.