Prepare the ingredients by gathering fresh oregano leaves, garlic, anchovy (if using), raw pistachios, lemon juice, olive oil, salt, and pepper. Clean the oregano leaves and set up your food processor.

In the food processor, combine oregano leaves, peeled garlic cloves, anchovy, and raw pistachios. Pulse for 15-20 seconds until finely chopped.

With the processor running on low, gradually drizzle in the olive oil and process for another 30-45 seconds until smooth.

Add fresh lemon juice, a pinch of salt, and ground pepper. Blend for an additional 20-30 seconds until well combined.

Taste the pesto and adjust seasoning as needed. Transfer to a serving dish and enjoy!