Chocolate Roulade with Chestnut Filling

Why I Love This Recipe
This cake is my sister's specialty. It's easy to make and it looks so exotic and fancy.
Ingredients You'll Need
Cake:
5 eggs, separated
1/3 c plus 1 tbs sugar
2 tbs self-rising cake flour
2 1/2 tbs cocoa powder
1 tsp vanilla extract
Filling:
1 c heavy cream
About 8 oz sweetened chestnut puree
Candied chestnuts, cut up into tiny pieces (about 3 tbs total)
Frosting:
4 oz chocolate chips
1/2 c heavy cream
Directions
Preheat the oven to 400F.
Grease, line with parchment, grease again and flour a half size oven sheet (13"x18").
Separate the egg yolks from the whites.
Add 1/3 c sugar and vanilla extract to the egg yolks and beat until light and fluffy, for about 3 minutes.
Sift the cocoa powder and cake flour on the yolk mixture and mix until uniformly mixed.
Now beat the egg whites until soft peaks form, add the reserved tbs of sugar and continue beating until stiff peaks start to form.
Carefully and gently mix the whites into the chocolatey yolk mixture, and stir until whites are totally incorporated.
Pour into the prepared sheet, level the batter with a spatula and bake in the preheated oven until the cake starts to shrink from the sides. That takes only a couple of minutes at this high oven temperature, so do not leave the kitchen for long.
Cool the cake a little, then turn it onto a cocoa-dusted clean kitchen towel, and carefully peel off the parchment.
For the filling, beat 1 c of heavy cream until almost firm.
Mix in the chestnut puree and fold in the bits of candied chestnut.
Spread this on the sheet of cake.
Starting from the shorter side, roll the cake tightly.
For the frosting, melt the chocolate chips and stir in the heavy cream.
Whip the mixture to spreading consistency. (If you don't whip, it has a glaze consistency which also works well.)
Frost the cake.
If you desire, decorate the top with rosettes of whipped cream and candied chestnut pieces.