Stir yeast with sugar until liquid. Put 1/2 teaspoon salt, flour, oil and 150 ml lukewarm water in a bowl. Add yeast and knead with the dough hooks of the hand mixer to a smooth dough. Cover and leave to rise in a warm place for about 40 minutes. For the topping, wash the asparagus, cut off the lower woody ends of both types of asparagus, peel the white asparagus. Cook the white asparagus in boiling salted water for 12 minutes.
Add green asparagus after 5 minutes of cooking time. Wash the herbs, dab dry, put aside some chervil for garnishing. Chop the rest of the herbs or cut the chives into small rolls. Mix crème fraîche with herbs and eggs. Season with salt and pepper. Drain asparagus, rinse with cold water and cut into slices at an angle. Knead the dough once again on a floured work surface. Roll out rectangularly (approx. 27 x 42 cm). Grease baking tray (25 x 40 cm) and line with the dough. Put approx. 2/3 of the herb cream on the dough and spread. Spread asparagus on top. Pour the rest of the icing over it.
Roll out rectangularly (approx. 27 x 42 cm). Grease baking tray (25 x 40 cm) and line with the dough. Put approx. 2/3 of the herb cream on the dough and spread. Spread asparagus on top. Pour the rest of the icing over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) on the lower rack for 30-40 minutes. Cut ham lengthwise into strips. Cover cake with Parma ham and garnish with chervil
40 minutes waiting time