Mix 250 g flour, eggs, 1/2 teaspoon salt and milk to a smooth dough and let it swell for 10 minutes. Wash the asparagus, cut off the woody ends. Melt the fat in a saucepan. Sweat the remaining flour in it, deglaze with the stock and bring to the boil while stirring. Let simmer for 5 minutes at low heat.
Refine with crème fraîche and season to taste with salt, pepper and lemon juice. Keep warm. Cook the asparagus in boiling salted water for about 10 minutes. In the meantime, heat the oil in a pan in portions. Bake 8 pancakes one after the other from the batter, keep warm. Cut salmon into strips. Chervil roughly chop and add to the sauce with the salmon. Spread asparagus on the pancakes. Fold the pancakes over and pour the sauce over them.
Bake 8 pancakes one after the other from the batter, keep warm. Cut salmon into strips. Chervil roughly chop and add to the sauce with the salmon. Spread asparagus on the pancakes. Fold the pancakes over and pour the sauce over them. Garnish with lemon and chervil