Defrost the puff pastry. Place 2 slices on top of each other and roll out 1 rectangle (approx. 24 x 32 cm) on a little flour. Prick several times with a fork. Place on 2 baking trays lined with baking paper and let rest in a cool place for about 15 minutes. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/gas: level 3) for about 15 minutes. Cooling down
Cut the edges of the puff pastry sheets straight. Cut both plates in half lengthwise to make a total of 4 rectangles (approx. 10 x 27 cm). Place 2 plates on 1 piece of aluminium foil (approx. 40 x 60 cm) each, fold the foil all around to a 5-6 cm high edge and bend up. Coat the inside of the aluminium edge with oil
Separate eggs. Beat egg whites and 1 pinch of salt until stiff. While continuing to beat, pour in 1 tablespoon of sugar. Keep beating until the sugar is dissolved. Stir 1/4 l milk, egg yolk, pudding powder and the rest of the sugar until smooth. Boil up the rest of the milk. Stir in pudding powder and bring to the boil again briefly. Fold in the beaten egg white. Let the pudding cool down for 5-10 minutes. Spread the pudding on the lower dough plates. Chill for about 5 hours.
Cut the remaining 2 plates into 5 pieces each (approx. 5 x 10 cm)
Stir icing sugar and lemon juice until smooth. Spread the puff pastry pieces with it, dry
Loosen aluminium foil edges. Place 5 pieces of dough on each pudding strip. Divide both strips into 5 slices each