Tomato Soup

from Gypsy Café in Westwood, Los Angeles

1 tablespoon oil or butter
1 red onion, chopped
1 large baking (russet) potato, baked and peeled
4 cups tomato sauce
1/2 teaspoon baking soda
2 cups half-n-half
2 tablespoons grated Parmesan cheese
1/2 teaspoon chicken soup base or bouillon
1/2 cup hot water
dash of dried oregano

Heat oil or butter in skillet over medium heat.  Add onion and saute until tender, about 5 minutes.  Place onion and potato in a food processor and puree until smooth.  Combine tomato sauce with baking soda in a stockpot or large saucepan, and add half-n-half.  Bring to a boil and simmer 10 to 15 minutes.  Add potato-onion mixture to tomato sauce and cook, stirring occasionally, until thick and smooth.  Add cheese.  Mix chicken base with water and stir into soup; simmer over low heat for 5-10 minutes.  Add dash of oregano before serving.  Approximately 150 calories per cup (using butter and regular half-n-half).