Heat 1 tablespoon of oil in a pan over medium heat. Add onions and fry for about 5 minutes until translucent. Add apples and pineapple pieces, and stew vigorously over medium heat for about 5 minutes. Add pineapple juice and scrape up any browned bits from the bottom of the pan. Season generously with salt, pepper, and curry powder. Bring to a boil, then transfer to a larger casserole dish.
Wipe out the pan and heat oil in it over medium-high heat. Rub chicken legs with salt and pepper, then fry on both sides until golden brown (about 8-10 minutes total). Place on the fruit bed in the casserole.
Cook in the oven at 200°C (392°F) for about 60 minutes (add 15 minutes if using frozen chicken legs), until the chicken reaches an internal temperature of 74°C (165°F).