Step 1

Place 2 quarts water in a large saucepan, and bring to a boil over high. Add winter greens; cook, stirring often, until bright green and slightly wilted, about 1 minute. Drain in a colander, and rinse under cold water. Squeeze firmly to remove as much liquid as possible over sink, and transfer to a food processor.

Step 2

Add walnuts and garlic to greens in food processor, and pulse until finely chopped, about 8 pulses, stopping to scrape down sides as needed. Add olive oil, grated Parmesan cheese, honey, lemon zest, lemon juice, and kosher salt; process until well blended, about 20 seconds. Transfer to an airtight container. Press plastic wrap directly onto surface of pesto, and cover with lid. Chill up to 3 days.