1/2 a clove of garlic
1/3 of a white onion
1 serrano chile
1 teaspoon of sea salt
First, roast the garlic and the chile. Then remove them from their blackened skins. Then put the roasted chile and roasted garlic in to a blender with the rinsed tomatillos avocado and the lime. Blend to a creamy consistency.
Chop the onion (to taste, I like onion so we used 1/3), and then put in a strainer. Rinse. Mix in to the salsa.
One tip - we actually used 1 whole lime and the result was pretty tart. I'd probably cut that in half the next time we make this (my recommended amounts are above).