Start by heating the oil in a frying pan which you can also use under the grill over a medium heat. Add the onion and fry for a few minutes. Add the garlic and cook for a little longer.
Once the onion and garlic has softened add the tomatoes and courgettes followed by the tomato puree and all the spices along with a good sprinkling of salt and pepper. Cook over a medium heat for 20 minutes until everything is softened and the tomatoes have released their liquid.
Heat the grill to medium high heat. Remove the pan from the heat and place the slices of halloumi across the top of the vegetables. Place under the grill for a few minutes until the cheese has browned. Sprinkle with basil before serving.