Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   4      medium        potatoes -- peeled
     1/2  teaspoon      turmeric
   1      tablespoon    corn oil
   1      tablespoon    chana dal
   1      tablespoon    urad dal
   2                    red chiles -- dried, crushed
   2      teaspoons     mustard seeds
   1      1" piece      ginger - peeled and minced
   2                    fresh green chiles -- minced
   1      large         onion -- thinly sliced
                        salt to taste
   1      teaspoon      fresh lemon juice

Preparation:

Cut potatoes into 2-inch cubes, boil until tender and drain. Add half the turmeric and mash lightly with a large fork. It should still be quite chunky. Keep warm. Heat oil in a medium saucepan or skillet until hot. Add ginger and fresh green chiles. Stir for 3 minutes. Add sliced onion, salt and remaining turmeric. Cook until onion is soft and transparent. Add a few drops of water if mixture looks too dry. Add to potatoes and mix well. Add lemon juice. Serve warm. Source: Sue Sista of "Sue's India Cuisine", San Jose and Mountain View