To make the cake:
Preheat the oven to 350 degrees. Lightly butter and flour one cookie sheet or baking pan (with one-inch sides). Boil the water and add slowly to the cocoa powder mix, whisk together until thoroughly combined. Set aside to cool.
Sift the flour together with the baking powder, baking soda and salt. Soften the butter, sugar, vanilla bean and vanilla extract in a bowl or electric mixer fitted with a whisk. Mix for 5 minutes until light and fluffy.
Add the sifted dry ingredients in thirds, alternating with the cocoa liquid in seconds. Stir very slowly to prevent splatters of chocolate and flour.
Pour the batter into the prepared baking sheet and bake for 25 minutes or until the center is set. It should slightly resist the pressure of your finger. Let the cake rest for 15 minutes before unmolding. Once removed from the cake pans, let cool completely.
To make the filling:
Melt the chocolate in a double boiler, over gentle heat. Boil the cream and the chili powders, and add to the melted chocolate. Stir to combine and set aside. Let cool to room temperature. When the chocolate reaches room temperature, use a balloon whisk to whip in the softened butter for 3 minutes until the mixture is light, fluffy and lightened in color.
To make the frosting:
Place the cream and sugar in an electric mixer fitted with a balloon whisk. Whisk until light and fluffy. (Be careful not over whisk the cream or you may make sweetened butter!)
Now let's put it all together! Using a heart-shaped cookie cutter, cut out six hearts from the cake. Pour the ganache filling into a homemade pastry bag.
Pipe the ganache filling in a heart shape around the border of the cake, leaving a 1/2 inch space. Place another layer of cake on top of the ganache and pipe the ganache the same way. Top with the third piece of cake and you're ready to frost. Repeat the process with the remaining cake hearts.
Using a spatula, carefully frost the cake with the whipped cream. If you like, decorate the top of the cake with rose petals and line the bottom with the green pistachios.
Published on January 01, 2006