this is my recipe for pesto, the classic basil, garlic, olive oil pasta sauce. A prerequisite for my recipe is a food processor - you can do it with a mortar and pestle (and there’s reasons to do so) but it takes an hour of manual labor instead of five minutes.
for a pound of pasta
ingredients
- basil, a three or four big bunches or two plastic blister packages. trimmed of thick stems
- garlic, three to five cloves. I am a “more garlic the better” person but pesto is the exception. because the garlic is raw and only warmed up by the residual heat of the pasta, it can easily overwhelm the rest of the flavors
- grated parmesan, meaning parmegiano reggiano. if you can’t locate this or don’t want to spend the money, a romano is better than cheap parmesan. for the amount, if finely grated about half as much as the basil. this is imprecise because I don't measure this kind of thing, sorry! I would normally say "a good amount of cheese"
- pine nuts, or walnuts, about the same amount as the garlic
- extra virgin olive oil
- salt
- pepper
- cold butter, 2 tbsp
- a pound of pasta
method
Salt water1 and bring to a boil, and cook your pasta.
In the food processor, add the basil, garlic, cheese, and nuts. Run the processor for a minute or two, pausing to reincorporate bits that fly out of reach of the blades.
Add in a dash of salt and pepper, and a small amount of olive oil. You want to roughly break everything down first before these elements come into the mixture. Run the processor like before, and slowly add in olive oil until the viscosity is like a thick paste.
At this point, run the processor for a while, at least five minutes. You want to break down the ingredients completely, and you’ll notice the color will go from a dark green to a lighter green as this happens. The consistency of the pesto should still be thick but not able to hold any kind of shape.
Once your pasta is done, reserve some of the pasta water, and drain the rest. In the pot, emulsify2 the pesto, butter and some reserved pasta water with the pasta. Serve immediately.
1 If you’re unfamiliar with how to salt pasta water, it should be really salty. If you taste the water it should taste like sea water, as in you involuntarily spit it out if you taste it. This is extremely important!! When tasting the pasta later for doneness it should already be pleasantly salted.
2 Emulsifying pasta means to essentially create a glaze or sauce out of starchy pasta water and a fat of some kind, usually butter or cheese. Depending on the fat or other elements it can be extremely difficult to do and do consistently, but pesto is actually among the easier ones to accomplish. Essentially what you want to do is on the drained but warm noodles, toss your cold butter in and stir. As the butter melts, put in a dash (probably about a quarter to half cup) of the pasta water. Vigorously stir the pasta around the pot and it will emulsify the two into a sauce that perfectly coats the noodles. In this case you're doing that with the pesto which is already an emulsion.
IF your emulsion is too thin: let the pot stand uncovered for a minute or two. Stir it periodically, and it will thicken as the sauce cools and some water evaporates.
IF your emulsion is downright watery: take some of the water out and follow the thin fix above. Next time use less pasta water!
IF your emulsion is too thick: add more pasta water.
