Grate or slice the zucchini into thin slices and cut the tomato into cubes. Whisk the three eggs together with salt and pepper.
Heat the olive oil in a frying pan over medium-high heat. Cook the zucchini for a few minutes until soft and then add the tomato.
Pour the beaten eggs over the vegetables and lower the heat. Let the omelet set gently until the top is just cooked through.
Tear fresh basil over the omelet, fold it in half and slide it onto a plate. Serve immediately.