Preheat your oven to 350°F (175°C) and line a 10×15 inch baking sheet with parchment paper.

In a mixing bowl, beat the eggs and sugar together until the mixture is pale and fluffy.

Gradually add the vegetable oil and cooled brewed coffee, mixing until well combined.

Sift in the flour, baking powder, and salt, folding gently until you have a smooth batter.

Pour the batter into your prepared baking sheet, spreading it evenly.

Bake for 12-15 minutes, or until the edges are lightly golden and the center springs back when touched.

Once baked, quickly turn the cake out onto a clean kitchen towel dusted with powdered sugar.

Carefully peel off the parchment paper and roll the cake up gently with the towel while it's still hot. Let it cool completely in this shape.

For the filling, whip the heavy cream, powdered sugar, and optional instant coffee until soft peaks form.

Once cooled, unroll the cake, spread the coffee whipped cream generously over the surface, and re-roll the cake carefully.

Chill in the refrigerator for at least 30 minutes before slicing and serving.