This is a recipe for a bitter chocolate-flavored tart soufflé. First, mix chilled butter with cake flour and cocoa powder, then add egg yolks, whole eggs, cold water, salt, and granulated sugar to make a tart dough, and let it rest in the refrigerator for at least an hour. Cut out shapes from the rested dough, line a tart pan with them, and blind bake. Then brush with beaten egg and bake again until firm. Prepare the tart cups by greasing the inside with butter and granulated sugar once they have completely cooled. Next, mix together the egg yolks, granulated sugar, and cake flour for the soufflé batter, then add boiling milk and 70% cocoa chocolate and mix well. In a separate bowl, whisk the egg whites with granulated sugar until stiff peaks form to make a meringue, then gently fold it into the chocolate mixture, being careful not to deflate the foam. Pour the finished soufflé batter into the prepared tart cups and bake in the oven. Finishing it off with a dusting of cocoa powder creates a sophisticated dessert for adults, where the moist, soft soufflé base and the bitter, rich, and crispy tart crust come together in perfect harmony.