Drain the corn or cut the kernels of the cob. Grate the courgette roughly. Mince the garlic, finely chop the deseeded chilli, if used. Mix everything together in a bowl.
Whisk the eggs lightly in a small bowl, season with salt and pepper.
Heat the oil in a non-stick frying pan. Add the mixed vegetables and gently sauté, stirring, for 5 minutes, until soften.
Pour over the egg and let it spread out evenly. Put the lid on and cook for 5 minutes.
Meanwhile turn on the grill in your oven. Cut the cherry tomatoes in half. Put these on top of the frittata, put the lid back on.
When the grill is hot and the surface of the frittata is no longer runny, put the pan under the grill and brown for 2-3 minutes.
Slide the frittata onto a plate, let it cool slightly and cut it into wedges. Alternatively, let it cool completely and cut it into bite-sized squares.