1.
Preheat oven to 150°C.
2.
Whisk together the eggs, cream and milk in a bowl. Add the spring onion, trout, herbs and parmesan. Season with salt and pepper and stir to combine.
3.
Melt the butter in a 26cm frying pan (with an ovenproof handle) and add the egg mixture. Cook over very low heat, gently pulling the frittata away from the sides of the pan occasionally, until the base and sides are set (this can take up to 30 minutes). Transfer to the oven for 20 minutes until cooked through.
4.
Cut the frittata into wedges and serve warm with creme fraiche, salmon roe and chopped herbs, to garnish.