• 3 to 5 cloves garlic
• 1 cup pine nuts, slivered almonds or walnut halves
• 2 tablespoons grated Parmigiano-Reggiano cheese, or to taste (optional)
• 1 teaspoon freshly ground black pepper
• 1/2 teaspoon fine sea salt
• 4 packed cups chopped fresh basil leaves
• 1/2 cup extra-virgin olive oil, plus more for storage
• Juice of 2 lemons
• Crushed red pepper flakes to taste (optional)

1. Put the garlic in the bowl of a food processor and pulse until coarsely chopped.
2. Toss in the nuts, Parmesan, if using, pepper and salt and chop until the nuts are finely crushed, about 1 minute.
3. Add the basil, oil and lemon juice and pulse for 1 minute more, until smooth.
4. Stir in red pepper flakes, if desired.

To store, transfer the pesto to a sterilized jar with a tight-fitting lid. Pour a thin layer of olive oil on top of the pesto, seal and refrigerate up to 10 days or freeze up to 3 months.