We had tacos with the Golden Globes Sunday night, and the salsa - which started out simply as "well, this is what I got at Market Basket, what can I do with it?" - was so good that I've been trying to find other things to do with it for the rest of the week. (The tacos themselves were centered around pork belly, which was cured with chili con carne seasoning, simmered to soften the skin, smoked, and then cubed and deep-fried before being put on warm pita - in lieu of flour tortillas - smeared with the salsa and some monterey jack cheese.)
Fry up one onion, chopped, until it starts to soften; add a large amount of garlic (20 cloves or so) and continue to fry until the garlic gets some color; add five medium to large tomatilloes, a little Mexican oregano, a little chile pepper (I used dried jalapeno), and just enough water for it to all simmer in until the garlic is soft. If you have cilantro roots, add them at the simmering stage.
Puree everything until as smooth as possible, put back in the pot, and cook down until thick - not quite as thick as tomato paste, but certainly as thick or thicker as jarred salsa.
Puree again, this time adding the leaves from one large bunch of cilantro, and the flesh of one ripe avocado. The cilantro will be the bulk of the volume, so with an immersion blender it will take a fair bit of blending to get the sauce smooth - with a Cuisinart you'll be scraping the sides of the bowl a lot.
Season with a bit of salt and a lime's worth of juice.
It may sound like salsa verde mixed with guacamole, but the cilantro and garlic are really the focus - everything else is in a supporting role.