Heat the oil in a large frying pan over a medium heat and add the aubergine wedges, stirring well to make sure all the pieces are coated in the oil. Cook, stirring occasionally, for 6 minutes and then add the garlic. Continue to cook for 2 minutes or until the aubergine is tender and cooked through and the garlic is just turning golden. Stir in the tomato purée, soy sauc