For the Lemon Verbena Pesto, combine the lemon verbena, garlic, cheese, and nuts in a food processor and pulse to puree. Slowly add the olive oil with the processor running until the mixture thickens and emulsifies, about 1 minute. Season to taste with salt and pepper. The pesto will keep in the refrigerator for 7 to 10 days, or it may be frozen for up to 3 months.