For the vegetables
Heat at medium/high heat, the extra-virgin olive oil in a large frying pan, add the potatoes, garlic, onion, leeks, kale, cauliflower, red pepper and seasoning, stew gently, partially covered, for 15-20 mins, stirring occasionally until the potatoes are cooked.
Beat the eggs separately in a large bowl, then stir in the potatoes and vegetables with the parsley, season with sea salt and pepper.
To cook the omelette
Heat a medium frying pan to fit all the mix of the omelette. Add a teaspoon of oil to the pan and spread well to avoid the omelette sticking to the pan.
Tip everything into the pan and cook on a medium heat, for 5-8 minutes, using a spatula to shape inwards the corners of the omelette.
To flip the omelette
When almost set, carefully, invert on a plate and slide back into the pan and cook for 4-5 minutes. Alternatively, you can cook the omelette directly under a hot grill in the oven.
Slide gently on to a serving plate and serve with a fresh green salad.