To make the pesto, first toast the nuts. Pour the nuts in a dry, nonstick skillet and let cook for 5 to 8 minutes on medium heat. You want them golden but not burnt. You will be able to smell them when they are ready.
Next, add the garlic to the food processor and pulse until finely minced. When the garlic is chopped, add in the basil. Pulse everything until finely chopped as well. Add in the lemon zest, juice, walnuts, salt and pepper and blend everything to combine.
Lastly, add in the parmesan and blend while slowly drizzling in the olive oil. You may need more or less olive oil, just depending on how thick you want the pesto.
Taste the pesto to adjust any necessary seasonings. Enjoy!