Coarsely grate the cheese. Wash and peel the asparagus and cut off the woody ends. Cut the stalks, except for the tips, very diagonally into thin slices. Roll out the dough and place on a baking tray. Season sour cream with salt and pepper and spread it on the dough. Spread asparagus on top and season with salt. Sprinkle with cheese and ham.
Bake in the preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: see manufacturer) for approx. 15 minutes. Wash the chervil, shake dry, pluck the leaves from the stems and chop. Sprinkle the finished tarte flambée with chervil.