Makes about 2 cups
1 clove garlic, roughly chopped
¾ teaspoon salt, plus more as needed
⅓ cup olive oil, plus more as needed
½ cup parsley & stems (or arugula, watercress, etc.), roughly chopped
6 ounces nettles
⅓ cup toasted walnuts
1-2 lemons, juiced
Prepare an ice bath by filling a bowl with water and a decent amount of ice. Bring a pot of salted water to a boil, and (using tongs!) add your nettles. Blanch for 30 seconds, remove with a slotted spoon or mesh sieve and add to the ice bath immediately. Let sit for 5 minutes, then drain and gently wring out the additional water. Roughly chop the nettles and set aside (you’ll need about 1 cup chopped for the pesto).
Combine garlic and salt in the bowl of a food processor, and blend until garlic is finely chopped (just run for about 20 seconds). Scrape the sides of the food processor and add in olive oil. Run again until everything is relatively smooth, another 30 seconds or so. Add parsley and nettles, and process until everything starts to come together and greens are finely chopped, scraping down sides as necessary. Add walnuts, and pulse to combine, just so walnuts are broken down. Transfer everything to a bowl and add the juice of 1 lemon to start (see note), salt to taste, and more oil to reach your desired consistency. Add additional lemon juice to taste.
Note: Leave out the lemon juice unless you plan to use all the pesto in a day (this will help it keep longer; 5 days or so). Store the pesto in an air-tight container with a drizzle of olive oil on its surface, and add in lemon juice to taste just before using.
To Serve: Prepare pasta according to directions, and toss with pesto and a spoonful or two of pasta water in a large bowl. Season to taste with lemon juice, and top with a cheese of your choice.