How to cook
Add the spices and then the leeks and potatoes. Stir everything well.
Divide the lump of butter in half. Put one half in the pan and wait for it to melt.
Pour the mixture and bake it over low heat (the patatnik should not be more than 0.6″ (1.5 cm) thick). If you have a small pan, make two.
Turn it over with a large plate or a lid and before baking it on the other side, melt the other half of the butter.
The patatnik with leeks and potatoes is ready.