This lovely winter dessert requires a bit of organization. You will need to begin at least 3 hours before you plan to serve the dessert in order to leave time for the mousse to set. Have four bowls standing ready — a large bowl for whipping the egg whites, a medium bowl for whipping the cream, and small bowls for the chestnut purée and the egg yolks.
In the interests of efficiency, I recommend using canned or frozen chestnuts for this dessert — but if you have the time and the inclination, you can start with raw chestnuts, peel them with a sharp paring knife and boil them until they are tender. If using canned chestnuts, the best choice would be the unsweetened variety, but they can be hard to find. The recipe below is for sweetened canned chestnuts. If you begin instead with unsweetened or raw chestnuts, increase the amount of sugar by 1/4 cup (4 tbsp.).
As the mousse is rather rich, you can serve it in small quantities in little glasses or soufflé cups, accompanied by fruit or gingerbread, for example. Or you can serve it in a large bowl and have guests help themselves — à la bonne franquette, as the French say.
1 large can of chestnuts (1 pound, or 500 g., when drained)
2 cups (1/2 liter) water
1/2 cup sugar
1 tsp. vanilla extract or 1 tbsp. (1 packet) vanilla sugar
1-1/2 tsp. strong black coffee
1-1/2 tsp. brandy or grappa
1 cup (20 cl) chilled whipping cream
1/2 cup (10 cl) crème fraîche, sour cream or Greek yogurt
If using canned chestnuts, drain them into a sieve and rinse thoroughly.
Transfer the chestnuts to a pot. Add the water, sugar and vanilla. Set over medium heat and simmer for 15-20 minutes, until the chestnuts are soft.
Purée the chestnuts into a paste, using a hand blender or counter-top blender. If the mixture doesn’t blend well, add a little more water. The paste does not have to be perfectly smooth as it is nice to have a little texture in the mousse.
Transfer the puréed chestnuts to a clean bowl. Stir in the strong coffee and the brandy or grappa. Refrigerate for half an hour or more.
When the chestnut mixture has chilled and you are ready to proceed, separate the eggs, placing the whites in a large bowl and the yolks in a small bowl. Mix the yolks with a fork or wire whip until smooth. Set aside.
Using an electric beater, whip the chilled cream until it is quite firm.
Rinse your beaters and dry thoroughly.
Now whip the egg whites until they form stiff peaks. Transfer about one-quarter of the whites into the yolks and mix well. This will lighten the yolks. Pour the yolk mixture back into the whites and fold in with a rubber spatula, lifting the whites gently, until the mixture is evenly colored.
Remove the chestnut purée from the fridge and gently mix it into the whipped cream.
Now gently fold the chestnut mixture into the egg mixture.
Spoon the mousse into small glasses, small soufflé cups or one large bowl. Refrigerate until set, about 2 hours.
When ready to serve, top with dollops of crème fraîche, sour cream or Greek yogurt. Serves 8-10.