Trim the kale leaves of their thick stems, then blanch them in boiling water for about 3 minutes.
Drain the kale leaves in a colander and run them quickly under cold water. Squeeze them dry and chop them roughly.
Add the blanched kale leaves to the bowl of a food processor, along with the walnuts, garlic and a small pinch of salt. Pulse until you have a rough paste. Now run the processor continuously while you drizzle in enough olive oil to produce a smooth and dense paste.
Turn the paste out into a small mixing bowl. Mix in the grated cheese. If need be, thin out with more olive oil (or some of the kale cooking water) so you have a very thick but just pourable mixture. The oil should make it glisten.
Taste and adjust for seasoning.