Mix the lamb and pork mince together in a bowl.
Combine the pepper, onion, apples, ginger, coriander, and egg white with the meat mixture.
Shape into 2cm balls, coat with flour, and refrigerate for 30 minutes.
Heat 10ml olive oil in a pan and sauté the red onion for 3 minutes.
Add leeks and courgette to the pan and fry until lightly browned.
Stir in tomatoes, sugar, and vinegar, then simmer for 20 minutes.
Cool slightly and blend in a food processor until smooth.
Return the blended sauce to the pan.
Fry the meatballs in 15ml olive oil until golden-brown.
Add the sauce to the meatballs and simmer for 15 minutes.
Serve the meatballs and sauce over rice and garnish with basil.