Defrost puff pastry slices side by side at room temperature for 10-15 minutes. Wash the asparagus, drain and possibly cut off the ends. Pre-cook asparagus in boiling salted water for about 3 minutes.
Place on a sieve, rinse briefly under cold water, drain and allow to cool.
Grease tartlets with lift-off base (approx. 12 cm Ø) and dust lightly with flour. Roll out the puff pastry sheets a little larger (approx. 14 x 28 cm) and cut them in half crosswise. Line the tartlets with the dough and sprinkle the base thinly with breadcrumbs.
Halve the asparagus and distribute in the moulds. Wash the chervil, shake it dry and chop it, except for something to garnish. Mix sour cream, eggs, chervil, some salt and pepper. Pour the icing over the asparagus and sprinkle with almond flakes.
Bake in the preheated oven, lower shelf (electric oven: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 25-30 minutes. Remove the finished tartes from the moulds and garnish with chervil.