1. Separate egg yolks for the egg whites.
2. Utilizing a blender, beat egg yolks with sugar and vegetable oil till creamy.
3. Whisk egg whites till stiff peaks kind.
4. Fold egg whites into the yolk combination fastidiously, then sift in the flour and fold it into the batter too.
5. Divide the batter into 2 parts and blend one with cocoa powder and one other with cornstarch.
6. Pour the white half of the batter onto a parchment-covered baking sheet, and unfold evenly.
7. Bake for five minutes at 190°C/375°F.
8. Pour the chocolate batter on prime of the base layer and unfold it out evenly. Bake for 8 minutes.
9. Let the roll calm down, peel the parchment again, and unfold hazelnut cream on prime of the cake base. Roll tightly and go away in the fridge to set.
10. Rigorously slice the roll and dip every slice in melted chocolate, overlaying one aspect.