Preheat your oven to 325°F (163°C) and line an 8x12 inch cake pan with parchment paper, greasing the sides.

In a mixing bowl, whisk together egg yolks, whole fat milk, vegetable oil, and vanilla extract until smooth.

In a separate bowl, sift together cake flour, baking powder, sugar, and sea salt, then create a well and add the wet mixture, combining gently.

Whip egg whites until frothy, add cream of tartar, then gradually mix in sugar until stiff peaks form.

Fold the whipped egg whites into the batter in thirds, being careful not to deflate the mixture.

Pour the batter into the prepared pan and tap to remove air bubbles.

Bake for 10 to 12 minutes or until a skewer comes out clean, then cool for 5 minutes in the pan.

Invert the cake onto a cooling rack, remove parchment, and roll the cake tightly in fresh parchment paper to cool completely.

Chill heavy cream and other cream ingredients for at least 2 hours, dissolve gelatin in water as per directions.

Whip the chilled cream with sugar, instant coffee, and gelatin until stiff peaks form.

Unroll cooled cake and spread whipped cream evenly over it, then re-roll without parchment and refrigerate for 30 minutes.

Decorate the top with reserved whipped cream and serve chilled.