Place a pizza stone in the middle of the oven and preheat to 450°F (230°(C). Once the oven has reached 450° F (230°C), let the stone continue to heat for 15-30 minutes longer, without opening the door. 

In a small bowl, toss the onion with the vinegar,½ teaspoon olive oil, and salt and pepper to taste. Set aside.

To make the meatballs, in a large bowl, combine the pork and beef, the garlic, and the 2 tablespoons Parmesan. Season well with salt and pepper and mix gently with your hands. Form into mini meatballs, using a scant 1 teaspoon of the meat mixture for each and placing the finished meatballs on a plate as you work. Set aside.

On a floured pizza peel, stretch or roll out the pizza dough into a 12-inch (30-cm) oval, with even thickness across the oval. If the dough springs back, let it rest for about 10 minutes before continuing. Leaving a 1-inch (2.5-cm) border, spread the sauce over the dough and top with the mozzarella and the¼ cup (1 oz/30 g) Parmesan.

Distribute the meatballs evenly around the pizza and finish with the marinated onions. Brush the outside edge of the dough with olive oil and season the whole pizza lightly with salt and pepper.

Carefully slide the pizza from the peel onto the hot stone in the oven and bake for 10-12 minutes, or until the meatballs are cooked through and the crust is golden brown. Using the peel, transfer the pizza to a cutting board and scatter basil all over the top. Let cool for a few minutes, then slice and serve right away.