Make sure your kale leaves are washed well, any excess water is drained away, and any hard stems removed. Zest and juice the lemon.
Add the kale, 1/4 cup lemon juice, 1/2 tsp lemon zest, olive oil, garlic, walnuts, Parmesan, salt, and some freshly cracked pepper to a food processor. Process until the mixture is a fine textured paste. Taste and adjust the salt, pepper, or lemon if desired. If you want a runnier pesto for drizzling, add extra oil, or up to 2 Tbsp water.