Preheat the oven to 180°C.
Bring a large saucepan of salted water to the boil and blanch the vegetables for 2-3 minutes. Drain and refresh in iced water.
Heat the olive oil in a large, heatproof frying pan set over a medium heat. Whisk together the eggs with seasoning. Pour into the pan then add the blanched vegetables, arranging as evenly as possible in the setting egg.
Allow the base of the omelette to set for 1 minute then transfer to the oven to finish cooking for 4-5 minutes. Remove once the rest of the omelette has set and is cooked.
Turn out onto a chopping board and cut into triangle portions. Arrange stacked on serving plates until ready to serve.