Preparation / Directions:
Heat the vegetable oil in a medium skillet over moderate heat.
Cook the onions until soft, about 10 minutes. Transfer to a food processor fitted with the metal blade or a blender.
Add the remaining ingredients and puree, in batches if you are using a blender, until smooth.
Pass through a medium strainer, pressing with a spatula or wooden spoon to push through as much pulp as possible.
Pour into a saucepan, and add the salt. Bring to a boil, reduce to a simmer and cook, uncovered, 20 minutes.
Adjust the seasonings.
Set aside and cool for table salsa or use warm for red rice or chilaquiles.
Makes 1 1/2 quarts Store in the refrigerator 2-3 days or in the freezer for weeks.
SOURCE: Mesa Mexican, Mary Sue Milliken and Susan Feniger with Helena Siegel.