Place the puff pastry slices next to each other and defrost at room temperature for about 10 minutes. Whisk the egg with 2 tablespoons of cream. Wash the salmon, dab dry and cut each piece in half.
Sprinkle some breadcrumbs on 4 puff pastry slices in the middle. Place 2 salmon fillet halves on each. Wash the chervil and dab dry. Place a large stalk on each salmon. Put the rest of the chervil aside.
Season fish with salt and pepper. Sprinkle with remaining breadcrumbs. Brush the edges with egg. Place 4 slices of puff pastry on top, possibly pulling them a little larger. Press the edges firmly together. Notch the surface with the back of a knife.
Cut out 4 small circles (approx. 2 cm Ø) from 1 puff pastry slice, brush with a little egg and place in the middle of the packets. Put them in a cold place. Cut out small fish from the rest of the puff pastry, also put in a cold place.
Clean the carrots, leaving a little green, peel and wash. Clean, peel, wash and slice the kohlrabi. Cut the romanesco into florets and wash. Put the salmon and puff pastry fish on a baking tray lined with baking paper.
Brush everything with the rest of the egg. Sprinkle fish with sea salt. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes. Remove the fish after 8-10 minutes.
Cook the carrots in boiling salted water for about 12 minutes. After 5 minutes of cooking time add kohlrabi and romanesco. Put 125 ml cold water and 125 g cream in a pot. Stir in the contents of the bag with a whisk.
Bring to the boil briefly while stirring. Switch off the hob. Fold in 50 g of butter in small pieces until it has melted. Remove from the stove. Chop the rest of the chervil finely, except for a little to garnish. Stir the chervil into the hollandaise.
Drain the vegetables and let them drain. Melt 25 g butter, toss vegetables in it, season with salt and pepper. Arrange parcel with vegetables and sauce. Garnish with chervil and lemon wedges. Add salt fish.