Preheat your oven to 400°F (200°C). Cut the aubergines in half lengthwise and score the flesh in a crisscross pattern. Drizzle with olive oil, then sprinkle with salt and pepper. Place cut-side down on a baking sheet and roast for about 30 minutes until tender.
Once cool, scoop out the flesh into a mixing bowl. Add the pine nuts, lemon zest, Parmigiano Reggiano, breadcrumbs, egg white, and chopped basil. Season with salt and pepper, then mix until well combined.
Form the mixture into small meatballs, about the size of a golf ball, and place on a plate or baking sheet.
In a skillet, heat olive oil over medium heat. Fry the meatballs for about 3-4 minutes on each side, until golden brown and cooked through.
Warm the tomato sauce in a separate pan if using, and serve the meatballs with sauce drizzled on top or on the side for dipping.