Cheese Broth

Place the potatoes in a small pan and add salted water to cover. Boil until the potatoes are cooked but still firm, approximately 15 minutes. Drain and set aside.

Heat the oil in a medium saucepan over low heat and saute the onions until just translucent.

Puree the tomatoes in a blender until smooth and strain into the saucepan over the onions. Add the salt, baking soda, potatoes and water. Scald the milk separately and add it to the tomato mixture. Simmer for 2 to 3 minutes until all the ingredients are heated through.

Place the cheese in a soup tureen and pour in the hot soup, stirring until the cheese has melted. Pass the chiles so that each person may add 2 to his or her bowl and crush them with a spoon, or sprinkle the chile flakes in each bowl, before adding the soup. A small amount may also be strewn over the soup's surface for garnish, if desired.