Line a Swiss roll tin with butter and cover with parchment paper.
Whisk together egg yolks, 15 grams sugar and the vegetable oil. Mix to combine and set 2 tablespoons of this batter aside.
Add the cocoa powder to the remaining batter and set to one side.
In a bowl, whip 1 egg white until foamy, slowly add 2 teaspoons of sugar until you have stiff peaks. Add in the 2 tablespoons of batter you set aside, 1 teaspoon flour, and mix.
Put this mixture into a piping bag, and trace along an animal print template to create the outline. Bake in the oven at 170C for 1 minute then remove.
Meanwhile, whisk 3 egg whites until foamy then slowly add 50 grams caster sugar until you have stiff peaks. Take this mixture and fold it into the cocoa batter you set aside earlier. Fold in the remaining flour, ensuring there are no pockets of flour left. Be care not to knock too much of the air out.
Pour this mixture over top of your cooked white batter and spread it evenly into the corners of your tray. Bake for 12-14 minutes at 170C or until springy to the touch.
Boil the 25 grams sugar and 25 grams water to create a simple sugar syrup.
Once the cake has cooked, remove the parchment paper, spread over the sugar syrup on the side without the pattern and allow to cool.
Whisk the caramel and double cream together until you have soft peaks.
Spread this onto the cooled Swiss roll.
From the short edge, roll the Swiss roll together tightly into a log and serve.
