2 cups fresh basil leaves, packed
1/2 cup freshly grated Parmesan-Reggiano cheese (about 2 ounces)
1/2 cup extra virgin olive oil
1/3 cup pine nuts
3 garlic cloves, minced
1/4 teaspoon salt, more to taste
1/8 teaspoon freshly ground black pepper, more to taste
Place the basil leaves and pine nuts into the bowl of a food processor and pulse a several times.
Add the garlic and Parmesan or Romano cheese and pulse several times more. Scrape down the sides of the food processor with a rubber spatula.
While the food processor is running, slowly add the olive oil in a steady small stream. Adding the olive oil slowly, while the processor is running, will help it emulsify and help keep the olive oil from separating. Occasionally stop to scrape down the sides of the food processor.
Stir in salt and freshly ground black pepper, add more to taste.