1
Spread a clean kitchen cloth on the work surface. Immediately place the baked sponge, top side down, on the cloth and roll it lengthwise with the cloth and paper. Leave to cool.
2
Prepare the caramel. Heat the sugar in a large saucepan over a medium heat until melted. Be careful not to burn the caramel. Meanwhile, heat the sweet cream in a small saucepan and add it to the caramel, stirring. Cook, stirring, for 1-2 minutes to thicken the caramel, then melt the butter in the caramel and stir to combine the ingredients. Remove the caramel from the heat, season with salt and pour into a larger container to cool more quickly. Cover it so that it is touching the foil.
3
Whip the sweet cream and put it in a cold place. Blend the mascarpone cheese smooth with the condensed milk and vanilla paste. Fold in the whipped cream with a spatula and refrigerate until ready to use.
4
Unwrap the chilled roulade dough and carefully peel off the baking paper. Spread the caramel evenly over the whole dough and sprinkle with peanuts. Spoon the cream over the caramel and spread with a palette knife, leaving a 5 cm uncoated edge (otherwise the cream will leak out at the end). Then roll the dough tightly into a roulade with the help of a cloth.
5
Wrap the roulade in plastic wrap and put in the fridge to firm up the cream.
6
Bring the cream to the boil and pour it over the chocolate. Wait for one minute and mix smooth with a spatula. Add the oil and stir to combine. Remove the foil from the cooled roulade and place it on a wire rack. Cover with chocolate icing and sprinkle with peanuts. Place the roulade in the fridge to set the glaze.
7
Preheat the oven to 200°C. Whisk the eggs and sugar on high speed for 10 minutes. Sift the flour and cocoa over the egg mixture and fold in gently with a spatula. Spread the mixture evenly on a 38 x 30 cm baking tray (the inner dimensions of a household baking tray) lined with baking paper and bake for 7 minutes.