To make the crepes:
In a medium bowl, combine the cocoa powder, confectioners' sugar, flour, eggs, 3 tablespoons butter, and cream; whisk together until combined, being careful not to overmix. Add the milk, whisking continuously until the batter has an even and smooth consistency. Cover with plastic, and let rest at room temperature 30 minutes.
Pour 2 tablespoons batter into the pan, and swirl pan immediately, covering entire surface. Cook crepe until center looks set, 45 to 55 seconds. Using a spatula, carefully flip crepe; cook 1 minute more. Transfer to a plate.
Let cool completely, and cover with plastic wrap until ready to use. Store in a resealable plastic bag, refrigerated, up to 3 days, or frozen up to 1 month; bring to room temperature before assembling dessert.
Place the chopped chocolate in a medium bowl, and pour hot cream over chocolate. Let soften 5 minutes. Stir to a smooth consistency, and let cool completely. Store, refrigerated, in an airtight container up to 1 week. Bring sauce to room temperature before assembling dessert.
To make the chocolate souffle:
Place the egg whites and lemon juice in the bowl of an electric mixer fitted with the whisk attachment. Mix on medium speed until whites are frothy, about 3 minutes. Increase speed to medium high, and gradually add the sugar, whisking until meringue forms stiff, but not dry, peaks.
To assemble the dessert:
FOR THE CREPES AND ASSEMBLING THE DESSERT
FOR THE ESPRESSO SAUCE
FOR THE CHOCOLATE SOUFFLE