Flourless Chocolate Cake

Bahan-bahan (10 porsi)

• 12 tablespoons (1½ sticks) unsalted butter
• 6 oz semi-sweet chocolate, (best quality such as Ghiradelli, chopped)
• 1 teaspoon espresso powder/instant espresso ((optional, for a more intense chocolate flavor))
• 1¼ cups granulated sugar
• 5 large eggs
• 1 teaspoon vanilla extract
• ½ cup Dutch-process cocoa powder, (sifted (see note))
• 1½ cups heavy whipping cream, (cold)
• 3 tablespoons confectioners' sugar
• Cocoa powder and/or chocolate curls, (for decorating)