Be sure to remove any dirty or tough pieces, and then chop all your stems up into roughly the same size. If you don't have enough yet, throw them in a freezer bag until you have at least four to five cups. Now put it in a pot and add a generous amount of garlic, some salt, a VERY generous amount of olive oil, and then fill up about halfway with filtered water. Usually you will just begin to see the water when it's time to turn it off. Be careful, because you can always add more water later, but if you have too much you will end up with soup, not pesto. If you have a little over four cups of greens, add about a half a cup of olive oil. Today I had a huge bowl to cook and I was running low on olive oil so I supplemented with a gob of bacon fat on the principal that bacon fat improves most things, and greens particularly. If you do the same thing be sure to salt lightly since bacon fat is so salty.
Once the water heats up, it will start to look like this:
Bring the mixture to a boil and then turn it down to keep it at a simmer. Simmer until you can mash it up easily with a spoon. Taste for salt and add some if necessary. Transfer it to a blender or food processor once it has cooled and puree it thoroughly. If you think you added too much water, just leave some out when you puree it and add it back in until you like the consistency. Unlike basil pesto this is not a brilliant green but a disappointing pea soup mush. Sorry. At least it was made out of ingredients you would only have composted otherwise.
To use it right away, add it to a pound of hot cooked pasta with one cup of grated parmesan. I usually freeze it in two cup containers for a day when I don't feel like cooking.
I love trying new foods, cooking, and gardening. I hope to share these experiences on this site. Thanks for taking a look!