Bring a pot of salted water to a boil. At the same time, bring your sauce pan to medium high heat.
Once the water is boiling, drop in your pasta and cook according to package instructions.
Give your pistachios a rough chop and add them to your heated sauce pan. Toast until fragrant, approximately 3 to 5 minutes, then remove from the pan.
Reduce the heat to low and pour in your E.V.O.O. as well as your minced garlic. Cook your garlic until fragrant then add your lemon pesto. Stir to combine and pour in the heavy cream or half and half.
Once your pasta is al dente, transfer it directly to your sauce pan. Some pasta water should get transferred over with it to help loosen the pesto sauce. You can add as much pasta water as you'd like to reach your preferred consistency.
Add salt and pepper to taste. You could also add some chili oil or red pepper flakes to add heat. Once the sauce is to your liking, plate your pasta, top with parmesan cheese, fresh basil, toasted pistachios, and freshly ground pepper.
Serve immediately and enjoy!