So festive!

1 tablespoon espresso powder (very finely ground)
1/2 cup water
6 eggs
1 15.25- ounce box devil’s food cake mix
1/4 cup vegetable oil
1/2 cup sour cream
1 1/4- ounce envelope unflavored gelatin powder
1/4 cup granulated sugar
1/4 cup water
1 cup heavy cream
1 stick unsalted butter
3 cups confectioner’s sugar
1/4 cup milk (room temperature)
1 teaspoon vanilla extract
1/4 cup cocoa powder (to garnish)

For the Chocolate Cake: Preheat the oven to 375ºF. Spray a baking sheet with cooking spray and line with parchment paper. Spray the parchment with cooking spray and dust with cocoa powder. Set aside. Line a separate, same-sized baking sheet with a clean kitchen towel.
In a medium bowl, add the espresso powder and water. Whisk to combine.
In a stand mixer, on medium speed whisk eggs until thick and creamy. About 4 to 5 minutes. Add water mixture, cake mix and oil. Mix for another minute to combine.
Remove 3 1/2 cups of the batter to the prepared baking sheet, evening out the top into a smooth layer and bake until a toothpick inserted comes out clean, about 8-10 minutes. Reserve excess batter for another use or discard. Remove from the oven and carefully invert cake onto the towel-lined baking sheet. Peel away the parchment paper, discard, and carefully roll the cake up, like a jelly roll. Gently place rolled cake seam side down on a wire rack to cool completely.
For the Whipped Cream Sour Cream: In a medium bowl, add the sour cream and sprinkle the gelatin on top. Allow to sit for 1 minute, then whisk together. Meanwhile, in a small sauce pan over medium-high heat, add sugar and water and bring to a boil. Remove from heat and whisk into bloomed gelatin. Mix until thoroughly combined.
Using a stand mixer, whip cream until stiff peaks. In two batches, fold in sour cream mixture, until just combined.
Line a baking sheet with parchment paper.
Unroll the cake, and using an offset spatula, spread the cake evenly with the whipped cream sour cream, leaving a 1-inch border around the edges. Roll the cake once more and return to the wire rack, seam side down. Carefully transfer to lined baking sheet. Refrigerate while making the vanilla buttercream.
For the Vanilla Buttercream: Clean out the bowl of the standing mixer and fit it with the paddle attachment. Add the butter and cream until smooth and fluffy, about 2-3 minutes. Add the sugar, milk, and vanilla extract, mixing until light and fluffy.
To Assemble: Remove the Bouche de Noel from the refrigerator and cover the sides and top of the cake with vanilla buttercream, leaving the ends bare, evening icing out with an offset spatula. Allow the icing to dry for 5 minutes. Gently lay the parchment stencil over the cake and dust with cocoa powder. Remove the stencil, slice and serve immediately. If not serving immediately, refrigerate until ready to serve.
Tip: Place any remaining cake batter in a greased muffin tin and bake for a bonus treat!