Preheat oven to 350 degrees.
Roast walnuts for 8-10 minutes, until fragrant. Remove and set aside to cool.
Cube Parmesan cheese and then place in food processor and grind until finely grated.
Wash and stem the basil. Pat dry with a towel.
When walnuts have cooled, add them to the grated cheese in the food processor and processed until combined.
Add garlic and lemon juice and combine again.
Add the basil to the cheese, walnuts, garlic and lemon juice mixture. You may need to pack it down a bit.
Slowly add the olive oil until the pesto starts to form.
Add the salt.
Serve immediately as a dip with veggies, seeded crackers, grilled/roasted/sauteed meats or combine with pasta. Otherwise, keep refrigerated.