Preheat oven to 200°C fan bake. In an ovenproof pan, add the butter, leek and garlic, and cook over a medium heat. Stir constantly for 3-5 minutes or until the leek has softened. Scatter over the courgette, pumpkin chunks and grated cheese.
In a bowl, whisk together eggs, cream, ¼ cup Tatua Crème Fraîche and half of the herbs. Season, then pour over the vegetables. Leave to cook in the pan for 3-5 minutes, or until the edges of the frittata are starting to set.
Dollop the remaining Tatua Crème Fraîche over the frittata, then place into the oven for 10-12 minutes or until the eggs have set. Sprinkle over the remaining herbs and serve.