Separate the egg whites from the yolk. Add regular and vanilla sugar to the yolk and whisk until fluffy.
Add the all-purpose flour, vanilla pudding mix, rum, milk, and gently stir everything together. Boil 9 dl of milk, reduce the heat, and pour in the mixture. Cook until it thickens. Remove from heat and then fold in the egg whites, which we’ve whipped into stiff peaks, adding 10 g of sugar and vanilla sugar.
Pour the cooked mixture into a baking tray on top of the baked puff pastry and let it cool. Then, spread whipped cream on top and cover with the remaining puff pastry, which can be pre-cut into the desired shape.