SWEET POTATO AND CHICKEN RISOTTO

350 g (11 1/4 oz) sweet potato, peeled and chopped
4 - 4 1/2 cups chicken stock
1 cup dry white wine
1 tablespoon olive oil
1 tablespoon butter
2 leeks chopped
2 chicken breasts fillets chopped
2 cups arborio rice
1/3 cup shaved or grated parmesan cheese
2 tablespoons butter
cracked black pepper

Place sweet potato in a greased baking dish and bake at 180C (350F) for 25 minutes or until crisp. Place stock and wine in a saucepan and heat to a slow simmer. Place oil and butter in a heavy-based saucepan over medium heat. Add leek and cook until soft and golden. Add chicken to pan and cook for 4 minutes or until browned. Remove chicken mixture from pan using a slotted spoon and set aside.