Flourless Yule Log Cake with Mascarpone Cream

Preheat oven to 350°F (175°C) and line a 10x15 inch jelly roll pan with parchment paper. Whip egg yolks with 1/2 of the granulated sugar and vanilla until thick and pale ribbon stage.

In a separate clean bowl, whip egg whites with cream of tartar and remaining sugar until stiff, glossy peaks form. Gently fold the yolk mixture into the whites, sifting in cocoa powder and salt while folding to maintain aeration.

Spread batter into the prepared pan and bake for 10–12 minutes until the sponge springs back. Immediately invert the hot cake onto a cocoa-dusted kitchen towel, remove parchment, and roll the cake with the towel from the short end. Let cool completely.

Prepare the filling by whipping 1 cup heavy cream, mascarpone, powdered sugar, and espresso powder until stiff peaks form.

Prepare the ganache by heating 1/2 cup heavy cream and butter until simmering, then pour over chocolate chips. Let sit for 5 minutes and whisk until smooth.

Unroll the cooled cake, spread mascarpone filling evenly to the edges, and re-roll tightly. Frost the exterior with the chocolate ganache and use a fork to create a bark-like texture.