Heat the oven to 200C/fan 180C/gas 6. Toss the courgettes, onion and garlic with the olive oil in a large shallow baking dish or roasting tin. Season well and roast for 10 minutes.
Stir in the cherry tomatoes and sit the halloumi slices on top. Sprinkle over the cumin seeds and chilli flakes, if using. Cook for another 15 to 20 minutes until the tomatoes start to burst and release juice, and the halloumi is turning golden.
Squeeze the garlic cloves out of their skins and mash into the oil and juices in the baking dish, stirring it in. Spoon everything onto plates and serve with soft flatbreads and houmous or hot sauce, if you like.
Notes
This halloumi and mediterranean veg traybake recipe is easily adapted if you’re cooking for less or more people - I halved it the first time I made it, to feed 2 of us.