For the asparagus tart, first prepare the dough.
For the dough, knead all the ingredients together. Roll out the dough to the size of a baking tray, raising the edge slightly. Peel the asparagus and cut away the woody ends. Then cut the asparagus spears in half lengthwise. Cut the onion into rings.
First spread the raw ham on the dough, then spread the onion rings and asparagus spears on the dough. Mix well sour cream, eggs, herbs, season with salt and pepper. Spread the glaze on the tart and sprinkle the grated cheese on top.
Bake the tart at 180 degrees for about 30 minutes.