Cut potatoes into 1cm rings, place in a pot of cold salted water. Bring to boil then simmer for 2-3minutes, drain well.
Meanwhile, heat oil in a medium pan, sauté onion and leek then add potatoes. Add drained corn, season well and finish with chopped parsley.
In a large bowl whisk eggs, season, then add potato mixture.
Using potato pan, clean and return to the heat with 2-3 tbsp olive oil. Once hot add egg mix. Do not stir. Shake instead to ensure veg is well spread throughout mix. Cook for 3-4 minutes until the outside edges are set.
Place frittata under grill for 2-3 minutes to finish cooking until the top is golden.