Fruity Chicken with Apricot Puree

light olive oil 1/2 a small onion, chopped (approx 50g) 1 small garlic clove, crushed 75 g chicken breast, cut into pieces 150 g sweet potato, peeled & chopped 3 dried apricots, chopped 150 ml passata (sieved tomatoes) 150 ml chicken stock or water