Step 1

Saute onions in a large saucepan in oil until transparent.

Step 2

Add tomatoes and cook, stirring until tomatoes are softened.

Step 3

Cool and then puree in blender or food processor.

Step 4

Return to pan and add rest of ingredients, except tortilla strips and cheese.

Step 5

Simmer, stirring occasionally, about 30 minutes.

Step 6

Add tortilla strips and heat about ten minutes.

Step 7

Serve with additional tortilla chips and cheese.