Small celeriac foams in crust

Ingredients for 4 : 1 celeriac, 5 tablespoons of moutarde de Meaux®, 1 liter of milk, 3 tablespoons of heavy cream,  1 egg white, a knob of butter, salt and pepper.

Preparation : 15 min, cooking 45 min.

Peel the celeriac, take out the black parts and the eyes, then cut it into pieces of 5 side cm.

Pour out the celeriac into a saucepan with the milk, salt, pepper and let cooking during 30 min by taking care that the milk doesn't boil over.
 
When the celeriac is cooked, strain it and mash it with a potato masher.

Preheat your oven to 180° C.

Add 2 tablespoons of heavy cream and mix the egg white beated in snow, salt and pepper.
In a bolus, mix 5 tablespoons of moutarde de Meaux® with 1 tablespoon of heavy cream.

Butter 4 cups and fill them with mousse, pack well using a spoon then coat with mustard.

Put into an oven and let cook 10 or 15 min since the mustard formes a light crust.