For your benefit, I've tried to add some real measurements, but honestly, I always just kind of "wing" pesto. It's basil, garlic, and oil. Yes, you can add cheese (parmesan) and pine nuts, but I usually don't just because I don't have them on hand. The great thing about pesto is that you can also add other stuff. Like fresh spinach with your basil. Or make part of the basil arugula. Or maybe add some walnuts instead of those pine nuts. In any case, it's good. Just see what you can come up with. Taste as you go, and add more garlic, more basil, etc. until it meets your pesto standards.
Basic Pesto
makes a little less than 1 cup
2 cups fresh basil leaves
2 cloves garlic (or 2 tsp minced)
1/2 cupish olive oil (may need more if you add any "extras")
salt and pepper
Extras
arugula
spinach
walnuts
cheese
parsley (you can really just use this in place of basil too, if you really like parsley)
Place your ingredients in food processor (a blender will work, but I recommend you at least double the recipe). Process until as smooth as you like your pesto to be. Taste and adjust if necessary. Spoon into an empty ice cube tray and cover with plastic wrap. When frozen, you can either leave them and pop them out when you want pesto, or pop them all out into a zip-lock and store in your freezer. Because the olive oil and any nut oil (if you threw in any nuts) is best suited to low temperatures, I recommend letting the pesto cubes sit out for a bit so they defrost (you can leave the overnight in your fridge, as well) and then just tossing them in at the last second to your pasta, etc. This will help keep the good-for-you fatty acids intact. But, I promise it will still be delicious and nutritious even if you heat it up a bit more!