In a heavy skillet on medium heat, toast nuts with olive oil until they are warm and fragrant (~5 minutes).
1/4 cup nuts walnuts, 1/4 tsp olive oil
In a food processor, pulse the nuts/seeds into small pieces.
Add the basil, cheese, garlic, and salt and process until the mixture is finely chopped. Scrape down the sides as needed.
2 cups fresh basil, 1/3 cup shredded parmesan, 3 cloves garlic, 1/8 tsp kosher salt
With the machine running, slowly drizzle in olive oil until the mixture has come together.
1/3 cup olive oil
Notes
You’ll have a better overall consistency if you pulse the nuts/seeds in a food processor before adding the rest of the ingredients.
Pesto will oxidize (brown) very quickly after it’s made. Either make it right before you intend to serve it or immediately transfer it to the fridge in an air-tight container.