For the cake: Cut an x on the bottom of each chestnut. Place on a baking sheet and roast in a 220°C (approximately 430°F) oven until the chestnuts burst, about 25 minutes. Peel the chestnuts.
Place the chestnuts in a pot and cover with water. Add the cinnamon stick and lemon zest to the pot. Bring to a boil and simmer for 20 minutes. Drain the chestnuts and remove the cinnamon stick. Mash the chestnuts.
Puree the chestnuts with the sugar and almonds. Cook the mixture over low heat, while stirring, for 3 minutes. Allow to cool slightly before stirring in the egg yolks.
Place 2 spoons of the chestnut mixture on top of each baking wafer and smooth top. Moisten the spoon to making smoothing the batter easier. Allow to dry for several days.
For the topping: In a bowl, beat the egg whites until stiff. Gradually add the powdered sugar and lemon juice, and continue beating until thick. Spread on top of the cakes and allow to dry for several hours. Store in an airtight container.