Wash and peel the asparagus and cut off the woody ends generously. Cut the asparagus into pieces. Cook in boiling salted water with 1 pinch of sugar for 8-10 minutes. Drain well.
In the meantime, take the puff pastry out of the refrigerator and let it rest for about 10 minutes at room temperature. Rinse salmon, pat dry and dice.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). For the cast, wash dill, shake dry and cut finely. Stir eggs, sour cream and dill until smooth. Season with salt, pepper and nutmeg.
Line a springform pan (26 cm Ø) with baking paper. Unroll the dough and put it into the form. Cut off any excess dough, line the free areas at the edge of the tin with it and press it against the dough in the tin.
Sprinkle the dough base with breadcrumbs. Spread the asparagus and salmon on top and pour the icing on top.
Bake in a hot oven on the lowest shelf for about 50 minutes. Remove from the oven and leave to rest for about 5 minutes. Remove from the mould and serve.