Salsa Verde (green table sauce)
From Fonda San Miguel, Thirty Years of Food and Art

12 tomatillos, husked

2-4 Serrano chilies, chopped
10 sprigs cilantro, chopped
½ C chopped white onion (I used more)
2 T vegetable oil
2 garlic cloves, chopped
1 t sea salt
Sugar to taste
Put tomatillos in a 3-quart non-reactive (glass or stainless steel) saucepan and cover with water. Cook over medium heat until the tomatillos soften and their green color begins to fade, about 8-10 minutes. Drain the tomatillos, reserving 1 C of the cooking liquid. Combine the cooked tomatillos, chilies, cilantro, garlic, and onion in a blender and blend, using up to 1 C of the reserved cooking liquid to make a smooth, liquid puree. Heat the oil in the same saucepan over medium heat. Add the puree and salt, cook for 8-10 minutes, stirring often. Check seasoning and add a little sugar if tomatillos are bitter. Serve warm or chilled. Makes 3½-4 cups.
Variation: Cool the sauce and puree it in a blender with the flesh of 1 ripe avocado and ½ C sour cream. Use as a dip or a topping for chicken-filled enchiladas.
Note: I used about half of the avocado puree and added a little more sour cream. I also added a jalapeno along with the chilies.