Peel the zucchini and cut it into small pieces. Cut the onion into half rings and fry in vegetable oil al dente. Then add the zucchini, pass the garlic through the press.
Gently stir and simmer over low heat for 10 minutes. Cut the tomatoes into slices and add them to the vegetables. Add salt, ground pepper, mix and leave to simmer for another 10 minutes. Garnish with a sprig of basil before serving.