Step 1

Cook kale leaves in a large pot of boiling salted water until bright green and wilted, about 30 seconds. Transfer to a rimmed baking sheet with tongs; keep water boiling. Let kale cool slightly; wring out excess water with your hands.

Step 2

Cook pasta in pot of boiling water, stirring occasionally, until al dente.

Step 3

Blend nuts, oil, garlic, and ⅓ cup water in a blender or food processor until very smooth. Add kale and 1 oz. Parmesan. Purée, adding water 1 Tbsp. at a time as needed, until smooth. Transfer pesto to a large bowl.

Step 4

Using tongs, transfer pasta to bowl with pesto; add butter and ⅓ cup pasta cooking liquid. Toss, adding more pasta cooking liquid by the tablespoonful if needed, until sauce coats pasta. Divide among bowls; top with more Parmesan and a few grinds of pepper.