To make the crepe batter, combine the cocoa, eggs, vanilla, and coffee liqueur in a large bowl until well combined. Whisk in the flour and butter and mix until there are no lumps. Set aside.

In a heavy sauce pan scald the milk (bring to a low simmer before removing from the heat). Add 1/4 of the hot milk into the egg mixture, whisking constantly, to temper, then combine the remaining milk.

Chill the batter for 30 minutes.

To make the filling, in a medium bowl, combine the mascarpone, cream, powdered sugar, cocoa, vanilla, liqueur, and salt and mix until smooth and well combined. Set aside.

After the batter has chilled, place an 8″ nonstick omelet, saute, or crepe pan over medium heat. Spray it lightly with nonstick cooking spray.

Pour 1 1/2 ounces (about 1/4 cup) of batter into the center of the hot pan and swirl the pan until the batter coats the pan evenly. Cook until the edges release from the pan and the underside of the crepe slides easily in the pan, about one minute. Flip the crepe, or turn with a rubber spatula, and cook for 30 seconds to 1 minute on the second side.

Remove to a plate and stack the cooked crepes between layers of parchment or waxed paper.

To assemble, spread a thin layer of the mascarpone mixture on the center of the crepe. Lay a line of bananas down the center, then roll into a tube. Alternately, you can spread the mascarpone over 1/4 of the crepe, lay a few bananas on top, then fold the crepe in half, and then in half again.

Serve with a dusting of powdered sugar.