Thaw the kale in a sieve (possibly in the microwave).
Knead a smooth shortcrust pastry from the flour, butter, egg, salt and water, wrap in aluminum foil until you are ready to use it and refrigerate.
In the meantime, cut the sausages into thin slices and squeeze out the kale well.
Sweat the finely chopped onion in a large pan until translucent, add the sausage and fry a little. Add the kale, salt and pepper and pour in some water. Put a lid on the pan and let simmer for about 10 minutes.
Mix the sour cream, cream, eggs and the two types of mustard together and season with salt and pepper. Season the cooled kale with salt, pepper, allspice and sugar. Finely grate both types of cheese.
Preheat the oven to 180 degrees top / bottom heat. Grease the quiche pan (about 30 cm) with a little butter. Roll out the dough on a floured surface to the size of the form and line the form with it, cut off any protruding edges.
Put the cooled kale on the dough, pour the icing over it and sprinkle with cheese. Bake for about 35 - 40 minutes. Let cool down a bit before eating.