Place puff pastry slices next to each other and defrost at room temperature for about 20 minutes. Clean and wash the spinach, blanch in boiling salted water and rinse immediately in cold water.
Wash the salmon, dab dry and season with salt, pepper and lemon juice. Whisk egg yolk and milk. Cut out flowers from a slice of puff pastry. Cut the remaining puff pastry slices in half and roll them out on a floured work surface large enough to wrap the fish slices in.
First wrap the fish slices in spinach, then in puff pastry. Coat the seam with egg yolk mixture and press on. Coat the packs completely with egg yolk mixture. Spread the blossoms on the packs and coat them as well.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 15 minutes. Remove fish from the oven, cut into thirds and arrange on a plate. Garnish with dill and lime.