Step 1

Blanch kale stems and leaves in boiling, lightly salted water to soften slightly and bring out their chlorophyll, about 1 minute. Remove kale from boiling water and immediately immerse in ice water. (This will shock the leaves to stop the cooking process and help retain their vivid green color.) Remove the kale from the water and squeeze it dry.

Step 2

Add kale stems and leaves, basil, cheese, pistachios, and parsley to a food processor and pulse until combined. Season with salt and pepper.

Step 3

With the food processor still running, slowly add the olive oil in a steady stream and process until smooth and incorporated.

Step 4

Fold in lemon zest and immediately serve over cooked pasta. Or, pesto can be stored in the refrigerator in an airtight container with a tight-fitting lid for up to a week.