Preheat your oven to 375 degrees F. Line a 10"x15" jelly-roll pan with parchment paper. Spray the parchment with cooking spray.
In the bowl of a standing mixer, add the eggs. Beat for about 5 minutes while gradually adding in the sugar. Continue to beat until the eggs become pale and lemon-colored.
Sift the flour, baking powder, salt, and cocoa over the bowl and gently fold the dry ingredients into the egg mixture. Add the coffee and vanilla and fold..
Pour the cake batter into your prepared jelly roll pan and bake in the preheated oven for 15 minutes. The cake is done when it pulls away from the sides of the pan and springs back when you gently press into it.
This is when the recipe gets kind of weird. Please stick with me. Spread out a clean hand towel and coat it with confectioners sugar. While the cake is still hot, turn it out onto the hand towel and then carefully roll the cake and the towel from the longer side up. Let the cake cool completely rolled up into the towel.
Once the cake has cooled, make the whipped cream. Add the cream to a bowl and whip, gradually adding the sugar and vanilla until smooth and creamy.
Unroll the cake and spread the whipped cream in an even layer over the top.
Roll the cake back up, enclosing the whipped cream, and transfer it to the fridge to set for a half-hour or so.
While the sets bakes, make your chocolate buttercream. I reduced the butter to 1 1/2 sticks and added 3 tablespoons of cream cheese. It turned out ultra-rich and creamy. Once the chocolate roll has set, frost it with the chocolate buttercream and sift powdered sugar over the top. Merry Christmas!