Defrost the slices of dough on a floured surface. Separate the egg. Halve the slices. Place 10 halves on a baking tray rinsed with cold water. Brush the edges with egg white. Make a rectangle out of the remaining halves, leaving a margin of 1 1/2 cm wide.
Place the rim pieces on the dough halves and press them down slightly. Place the remaining pieces of dough on a 2. rinsed baking tray. Whisk the egg yolks with some water. Brush the edges and lid with it. Leave to rest for about 1 hour.
Bake both trays one after the other in the preheated oven (electric oven: 225 ° C/ gas: level 4) for 12-15 minutes. Remove from the baking tray and allow to cool. Mix 3 tablespoons of milk, pudding powder and sugar.
Boil up the rest of the milk. Add pudding powder while stirring, bring to the boil. Pour the gooseberries onto a sieve and collect the juice. Whip cream and vanilla sugar until stiff. Stir half into the pudding, fill into the puff pastry slices and smooth them down.
Spread gooseberries over it. Gradually stir the cake glaze powder with 1/4 litre gooseberry juice until smooth and bring to the boil while stirring. Pour the icing over the fruit. Let it cool down. Pour the rest of the cream into a piping bag with a star-shaped spout.
Decorate gooseberry slices with it. Put a bonnet on top.