Start by washing 2 cups of fresh basil leaves under cold running water. Gently pat them dry with a kitchen towel, then remove the leaves from the stems.

In a food processor or blender, combine the prepared basil leaves, 1/2 cup grated Parmesan cheese, and 1/2 cup of walnuts. Add in 2-3 peeled garlic cloves and 1/2 teaspoon of salt. Pour in 1/3 cup of olive oil and 1/3 cup of lemon juice.

Pulse the ingredients together for about 30 seconds, then scrape down the sides of the bowl and continue blending until smooth.

Taste the pesto and adjust salt or lemon juice as needed, then blend briefly to incorporate any adjustments.

Transfer the finished pesto into an airtight container, leaving about 1/2 inch of headroom if using a jar. Seal tightly and store in the refrigerator for up to one week.