Preheat the oven to 180°C. Prepare the 43 × 37,6 cm baking sheet with attached baking paper.
Start by mixing the yolks with sugars until creamy. Then continue by slowly adding oil, water, flour, baking powder, and cocoa powder.
Whisk the egg whites in a separate bowl and gently fold them into the batter. Pour the batter onto the baking sheet.
Prepare your pudding by the instructions on the product. Once the pudding is cold, add the pudding into the cake batter - one tablespoon at a time.
Bake for 15 minutes or until the toothpick comes out clean. Let the cake cool completely.
In another bowl, mix together sour cream and powdered whipped cream.
When the cream is stiff, add a generous layer on top of the cake. Sprinkle with some shredded chocolate and let cool in the fridge for at least 4 hours.