Cooking Steps

1. Preheat oven to 350°F. Grease an 8 inch cake pan and line the bottom of the pan with parchment paper; set aside.
2. Combined the chocolate and the butter in a stainless steel bowl or double boiler. Place the bowl over, but not touching, a pan of simmering water to melt the butter and chocolate, mixing with a rubber spatula to make sure there are no lumps. Remove the chocolate mixture from the heat.
3. In a large mixing bowl beat egg yolks with an electric mixer on high speed until they triple in volume. Carefully fold the beaten egg yolks into the chocolate mixture.
4. Pour the batter into the prepared cake pan. Put the cake pan in a roasting pan. Put the roasting pan on a baking rack in the oven. Poor enough boiling water into the roasting pan to reach halfway up the sides of the cake pan. Bake for 25 minutes. Remove from the oven and keep in the water for another five minutes. Remove cake pan from the roasting pan.
5. Chill cake in refrigerator for 2 to 3 hours. Put a plate over the cake pan and invert to remove cake. Put another plate on the bottom of the cake pan and flip again to get it right side up. Sprinkle cake with cocoa powder; top with fresh berries and mint leaves.