Prepare the pudding with the milk and 2 tbsp sugar. Leave it to cool. Divide the puff pastry into 2 parts. Roll out each one to the size of the oven dish in which you'll be baking.
Put one of the sheets in the oven dish after covering it with baking paper. It has to cover the sides as well.
Pour in the grated apples, drained of their juice. Sprinkle 2-3 tbsp sugar, cinnamon, ground walnuts and raisins.
Pour the cooled pudding on top and cover with the 2nd sheet. Make cuts along the top and smear with egg yolk beaten with milk. Bake at 356°F (180 °C) for 20 min.
Sprinkle with powdered sugar.