Finely chop the onion and slice the courgettes lengthways into slices.

To make the sauce heat the olive oil in a saucepan then add the onion sweating it until softened. Then add the tinned tomates, torn basil leaves and leave to simmer on a low heat while preparing the courgettes.

Add vegetable oil to a frying pan and heat gently. Meanwhile dust the courgettes in the flour then dip in the beaten egg. Once the oil is hot fry the courgettes on batches until they are golden.

Preheat the oven to 200 Celcius. Line a 20 x 22cm ovenproof dish with some of the sauce, then arange a layer of courgettes followed by another layer of tomato sauce, torn mozzarella and some of the torn basil leaves. Layer until you use up all the ingredients, finish with mozzarella on the top.

Cover with foil and bake for 20 minutes. Then remove the foil and continue to bake for a further 15 - 20 minutes until the top is golden. Remove from the oven and leave to rest for 5 minutes before serving.