Fill a large enamel-coated cast-iron Dutch oven halfway with water, and to a boil over medium heat. Working in batches if needed, add basil and spinach; cook, stirring occasionally, until vibrant green and wilted, 30 seconds to 1 minute. Remove with a slotted spoon, and immediately transfer to ice water. Let stand for a few minutes. Drain well. (Do not squeeze out excess moisture.)
In the work bowl of a food processor, pulse together drained basil and spinach, peanuts, and all remaining ingredients until smooth. Use immediately, or refrigerate in an airtight container for up to 1 week.
Notes
KITCHEN TIP: Blanching the basil and spinach before processing keeps the pesto from browning and helps it hold a bright green color for several days when stored in an airtight container. It’s the perfect make-ahead sauce for a quick weeknight pasta supper.
Recipe by Southern Cast Iron at https://southerncastiron.com/pesto-swirl-bread/