Preheat your oven to 350°F (175°C). Lightly grease a 13 x 18-inch rimmed baking sheet and line it with parchment paper.

In a medium bowl, whisk together the egg yolks, half of the sugar, cocoa powder, oil, water, vanilla, salt, and baking powder until smooth. Sift in the cake flour and whisk until no lumps remain.

Using a stand mixer or hand mixer, beat the egg whites with the remaining sugar until stiff peaks form. The meringue should be glossy and hold its shape.

Add one-third of the whipped egg whites into the chocolate mixture and gently combine. Repeat with the remaining meringue in two additions, folding gently with a whisk to keep as much air in the batter as possible.

Spread the batter evenly into the prepared baking sheet. Tap the pan lightly on the counter to remove large air bubbles.

Bake for 10–12 minutes, or until the cake springs back lightly when touched. Allow the cake to cool completely in the pan.

While the cake cools, place the ice cream in the refrigerator for about 30 minutes until it becomes smooth and easy to spread. If needed, let it sit at room temperature for a few additional minutes.

Spread the softened ice cream evenly across the cooled cake. Starting from one short side, gently roll the cake into a tight log, using the parchment paper to guide and support the roll.

Wrap the cake tightly in plastic wrap and freeze for at least 4 hours, or until completely firm.