Preheat the oven to 200°C (Gas 6). Butter 4 moulds.
Peel the potatoes and cut them in chunks of 2cm. Put the milk in a deep bowl and add the fresh herbs and then add the potatoes. Allow to cook for 20 minutes.
Add the mushrooms to the saucepan and mix to a soup. Bind with the potato starch or maïzena. Allow to cool.
Separate the eggs and set the egg whites aside. Mix the 2 egg yolks into the mixture.
Beat the 2 egg whites in a separate bowl then gently stir them back into the mixture.
Divide everything between 4 buttered moulds and put them in a preheated oven for 8 to 10 minutes.
