Take the tops off the courgettes and slice lengthways into slices about 1cm thick. Spread the slices over the chopping board and season with salt on both sides. Sprinkle the chilli flakes on and the zest of half the lemon. Make sure both sides of the slices are covered, you might need to rub them around a bit.
BBQ or grill the slices for about 10 minutes, or until soft. Make sure to turn the slices a few times.
While the courgette is cooking, add the yoghurt to a flat bowl or deep plate and season well with salt and pepper. Add the chopped mint, 1 tbsp lemon juice and the rest of the zest. Mix together.
Place the courgette slices on top of the yoghurt, drizzle with olive oil and top with mint leaves and chilli flakes. Enjoy!