1. Preheat the oven to 180 °C (6).
2. Trim and thinly slice the leeks and steam them for 8 minutes.
3. Divide them into 4 mini oval dishes and add butter dices.
4. Beat the eggs in a bowl, adding the cream, half of the parmesan and a pinch of nutmeg. Season to taste and mix.
5. Pour onto the leeks and add the remaining parmesan. Brown in the oven for 20 to 25 minutes.