If you need to grate your cheese, cut up your Parmesan wedge into chunks and put them in your food processor or blender. Chop them until the cheese is the right consistency. Rinse your spinach, if needed, and pat dry.
Add the spinach and all ingredients to the bowl of the food processor. Pulse until you have the consistency of a smooth paste, stopping once to scrape down the sides of the bowl.
Serve the pesto stirred into cooked pasta or use it as a topping for pizza, chicken or salmon. (See notes for ideas.) Store the pesto in the refrigerator up to one week or freeze it for longer.
For ideal texture, use a food processor instead of a blender. If you only have a blender, just pulse the ingredients instead of letting your blender run for too long, or you will end up with more of a liquid texture instead of a paste.
Make this with freshly grated Parmesan cheese, for best results. There’s no need to grate by hand if you have a blender or food processor.
Just cut up a Parmesan wedge into large chunks, toss them into the machine, and pulse until you have a nice consistency. (I use speed 7 on my Vitamix(affiliate link) and keep that grated cheese in the fridge for weeks.
If serving with pasta, you can put water on to boil in a pot on the stove and make your pesto in the meantime. When the pasta is done, drain it, return it to your pot, and add 3-4 four heaping tablespoons of pesto per pound of pasta, stirring and adding more to taste.