Peel the onion for the curry sauce, dice it finely, and roast it in a pot along with the diced apples.
Add curry, and roast well.
Add the reduced broth, and bring to a boil.
Add cream, and let simmer for 5-8 minutes.
Season with tamari, lemon juice, mango chutney, salt, and pepper.
Add the meatballs, and heat through.
The sauce should taste intense and be sour, sweet, and slightly spicy.