2 tablespoons liqueur such as cognac or kirsch (optional) or water
 
Bitter Chocolate Glaze
1 cup dark unsweetened cocoa, sifted
pinch of salt
⅔ cup heavy cream
⅓ cup unsalted butter
1⅓ granulated sugar
1 teaspoon vanilla
Instructions
Make the chestnut cream center:
Heat chestnuts in their liquid. Drain well. Mash to a fine puree. Cool. Cream chestnut puree with butter. Add confectioners, chocolate, and cognac or brandy. Chill until firm enough to mold.
Cut sponge sheet in half lengthwise, making two rectangles 16 inches long. Spread mocha buttercream on one rectangle. Shape chestnut puree into a roll, 16 inches long and no more than 1 ½ inches in diameter. If cream is very soft, use wax paper to help mold it.
Make the apricot glaze:
Heat apricot jam in a saucepan until boiling. Stir in water or liqueur.
Place the roll of chestnut cream in the center of the cake. Roll cake around the chestnut cream center, turning seam to the bottom. Brush roll with hot apricot glaze. Place them on a cake rack.
Make the Bitter Chocolate Glaze
Combine all ingredients except vanilla in a heavy saucepan. Cook over low heat, stirring constantly, until smooth and thick, about 5 minutes. Let mixture stop bubbling. Stir in vanilla. Use while hot.
Pour rich bitter-chocolate glaze over top and sides. Chill. Cut into ¾ inch slices, wiping knife after each slice.
Yield 16 slices.
Recipe by ImPECKable Eats at http://impeckableeats.com/2015/12/chocolate-chestnut-slices/