Preheat your oven to 400°F (200°C) and prepare a half sheet baking pan by lining it with parchment paper, ensuring you spray it lightly with nonstick spray.

In a medium bowl, whisk together 1 cup of all-purpose flour, 1/4 cup of cornstarch, 1/3 cup of cocoa powder, and a pinch of salt.

In a large mixing bowl, beat four egg yolks with 3/4 cup of granulated sugar and 1 teaspoon of vanilla extract until pale and fluffy, about 3-5 minutes.

Gently fold half of the dry mixture into the egg yolk blend until just incorporated, then repeat with the remaining dry ingredients.

In a clean mixing bowl, beat four egg whites until soft peaks form, then gradually add 1/4 cup of granulated sugar until you achieve stiff peaks.

Gently fold the whipped egg whites into the batter in three additions, being careful not to deflate the mixture.

Spread the batter evenly in the prepared baking pan and bake for 8-10 minutes until the cake springs back when lightly poked.

Once out of the oven, sprinkle a generous layer of confectioners’ sugar onto a kitchen towel and carefully invert the hot cake onto it.

In a mixing bowl, whip 1 1/2 cups of heavy cream with 1/4 cup of confectioners’ sugar and another teaspoon of vanilla extract until medium peaks form.

Unroll the cooled cake carefully, spread the whipped cream evenly across the surface, and then roll it tightly back up without the towel.

In a small saucepan, heat 1 cup of heavy cream over medium heat until it just begins to simmer; remove and pour over 8 ounces of chopped semi-sweet chocolate.

Once the ganache has cooled slightly, chill it until it thickens, then whip until fluffy and spread over the surface of the log cake.