Leyden, from Dutch: Leidse kaas, is a semi-hard, cumin and caraway seed flavoured cheese made in the Netherlands from cow's milk.

Leidse kaas is the most common type of komijnekaas—cheese that includes cumin as an ingredient—in the Netherlands.

About 30 minutes later, the curd is cut with a harp, stirred, and warmed to about 33 °C (91 °F) by pouring in hot whey.

This resulted in a byproduct of semi-skimmed (part skim) milk, which was usually fed to calves, as it was of limited value.

[2] Traditional farm-made Leidse kaas made in the west of the Netherlands is an EU and UK Protected Designation of Origin named Boeren-Leidse met sleutels.