In a food processor, pulse the basil, spinach, pine nuts, black pepper, lemon juice, and salt.
Blend until the mixture is well blended but still has some texture, pausing to scrape down the sides, as necessary.
Now add the olive oil in the food processor and pulse for a few seconds, scrape the sides, and pulse it again.
I like to use a rubber spatula to scrape the sides. Pesto is now ready.
Adjust the ingredients to your taste.