After you remove the ribs and stems, chop the kale up roughly. Blanch kale in a large pot of boiling salted water, about 30 seconds. Drain and rinse with cold water to cool (or dunk in a bath of icy water). Spin in a salad spinner or wring dry in a clean kitchen towel.

In a food processor, add garlic and give it a whir to mince it more finely. Add kale and walnuts and pulse until coarsely chopped. With motor running, add oil in a steady stream and process to a coarse purée. Add lemon juice, pecorino and season with salt and pepper to taste.