2 cups basil leaves, 1/2 cup grated parmesan cheese, 1/2 cup olive oil, 1/3 cup nuts, 3 garlic cloves, salt and pepper.
In a blender, combine the basil leaves, grated parmesan cheese, nuts and garlic cloves. Pulse a few times to begin breaking down the ingredients.
With the blender running, gradually pour in the extra-virgin olive oil in a steady stream. This will help emulsify the sauce.
Add salt and pepper to taste. Blend again until the pesto reaches your desired consistency.
You can use the pesto immediately, or store it in an airtight container in the refrigerator for up to a week.