Place the Parmesan cheese in the food processor and process for 30 seconds.
Add walnuts and garlic to food processor and process for 30 seconds to 1 minute.
Add in basil, the juice of half a lemon, salt and pepper.
With the food processor still on, stream in the olive oil until the pesto reaches your desired consistency. You may use a little more or less olive oil.
Use immediately for a spread or a sauce on pasta. Or store in the refrigerator or freezer to use at a later time.
Recipe by The Cottage Mama at https://thecottagemama.com/2013/09/walnut-basil-pesto-recipe/