Chestnut Cocoa Cake with mascarpone filling

I've been fascinated quite a while by the possibility of using chestnuts for baking. I discovered them about two years ago at the christmas markets where they were sold fresh roasted and I loved the nutty taste and floury consistency. Later I found out they were sold in the larger supermarkets and so they found the way to my kitchen. I used them mostly for savoury dishes, eg for last year's christmas dinner (post is in German) as filling or for this year's dinner together with brussel sprouts. I tried a version of Chocolate Chestnut Cake from Melanger before, but I did something wrong and the result was merely that what I had expected. Searching for a more dry and light version, I stumbled over dozen recipes involving chestnut flour or puree, none of which I had at hand. So I had to create something suitable for me and I think it worked out. The filling was the result of the idea of adding another interesting taste and a leftover ramble of my fridge. The Tonka beans were bought of pure curiositiy some days earlier and were the perfect match to the mascarpone...

Chestnut Cocoa Cake with mascarpone filling

Cake:

• 250 g whole chestnuts, roasted and shelled
• 225 g all-purpose flour
• 50 g cocoa
• 1 1/2 teaspoon baking powder
• 1/2 teaspoon salt
• 225 g butter, softenend
• 215 g light brown sugar
• 4 large eggs
• 1 teaspoon vanilla extract
• 150 ml heavy cream
• 50 ml buttermilk

Puree the cream and buttermilk with the chestnuts until smooth and set aside. Mix the dry ingredients. In a large bowl, beat the butter with the sugar until pale and fluffy. At eggs one at a time and beat well after each addition. Add the vanilla. Beat in flour mixture and chestnut puree alternly in two to three batches, starting with the flour mixture. Preheat oven to 180°C. Butter a springform pan and line the bottom with parchment paper, then fill in the batter. Bake for about 30 minutes or until a toothpick comes out clearly. Let cool on a rack. When cooled completely, cut horizontally in halves. Clean your springform and wrap it with cling film, put the first cake layer back into the form.

Filling:

• 250 g mascarpone
• 200 ml heavy cream
• 3 teaspoon Kalua or other coffee liquer (can be substituted with strongly brewed espresso)
• 4 tablespoon Dulce de leche
• half a tonka bean, grated

In a large bowl, beat the mascarpone with the Dulce de leche and the Kalua until completely combined. Add the cream little by little, beating continuously until the filling is light and airy. Add the grated tonka bean at the end. Cover the first cake layer evenly and place the second cake layer on top, pressing gently. Let rest into the refridgerator for at least two hours. Unmould, cut and serve.