Fry the onion and leeks in oil.
Drain them well and combine them with the eggs, cream, milk, salt, pepper and nutmeg with a hand blender.
Pour into individual flan moulds.
Cook in a bain-marie in the oven at 160ºC for 30 minutes.
Very finely shred the lettuce.
Mix it with the roughly chopped cashews and pistachios.
Dress with a vinaigrette of lemon, oil and salt.