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.

Siegel.