1-Preheat the oven to 350°F (177°C). Grease a jelly roll pan with nonstick spray or butter, then line it with parchment paper and grease the parchment as well.

2-Sift together the cake flour, cocoa powder, baking powder, and salt; set aside.

3-Using a mixer, beat the egg whites with 1/4 cup (50g) of the granulated sugar on high speed for 4 5 minutes until medium peaks form. Transfer to another bowl.

4-In the same bowl, beat the egg yolks with the remaining 1/2 cup (100g) granulated sugar for 1 minute. Add the vegetable oil, buttermilk or whole milk, vanilla extract, and espresso powder (if using). Beat on high speed for 2 minutes until the mixture is thin and bubbly.

5-Gently fold half of the whipped egg whites into the yolk mixture, then fold in the remaining egg whites.

6-Sift the flour mixture into the batter and fold gently until just combined, avoiding over-mixing.

7-Spread the batter evenly into the prepared pan and bake for 12 14 minutes, or until the cake springs back when lightly touched. Do not over-bake.

8-Dust a piece of parchment paper or a thin kitchen towel with about 2 tablespoons of cocoa powder. Immediately after baking, loosen the cake edges with a knife and invert it onto the prepared parchment or towel. Remove the baking parchment from the bottom of the cake.

9-Starting at the narrow end, roll the warm cake tightly with the parchment or towel and let it cool completely at room temperature for about 3 hours or up to one day. Do not refrigerate before unrolling.

10-In a mixer, whip the heavy cream, sugar, and vanilla extract to medium-stiff peaks. If using, beat in the marshmallow creme.

11-Carefully unroll the cooled cake, spread the whipped cream evenly over it (leaving a 1/2-inch border), and roll it back up without the parchment or towel. Place on a wire rack over a baking sheet.

12-For the ganache, heat the heavy cream until it simmers gently. Pour it over the chopped chocolate (and corn syrup if using). Let it sit for 2 3 minutes, then stir until smooth and glossy.

13-Pour the ganache over the cake roll, allowing excess to drip off, and refrigerate for 30 60 minutes before slicing.