Sweet Potato, Swiss Chard, and Red Lentil Soup

Really really really amazing soup. Perfect amount of spices and different textures. A great (and obvious) continuation of my Indian kick... From Cheap Healthy Good.

Ingredients:
2 onions, chopped
1 1/2 t cumin seeds
1 t black mustard seeds
2 t oil
1 T fresh ginger, chopped
3 cloves garlic, minced
2 sweet potatoes, peeled and cut into 1-inch cubes
8 c water
3 c dried red lentils, rinsed (Any kind of lentil or split pea would do)
1 T mild curry powder
1 bunch Swiss chard

Directions:
In a large pot, heat 1 t oil and cook onions until translucent, about 5 minutes.
Move onions aside in pot and add second teaspoon of oil and whole cumin and mustard seeds.
Stir seeds with spatula for about 30 seconds.

When mustard seeds begin to pop, stir together spices with onions.
Add ginger and garlic and cook for about 1 minute.
Add water, sweet potato, lentils, and curry powder and stir.
Bring to boil, then reduce heat and simmer, covered, for about an hour or until lentils are tender.

Wash and chop Swiss chard and set aside. (I rolled up leaves and cut them to make long ribbons. Also, I chopped the stems separately)
Stir dal occassionally to prevent sticking and burning.

When the dal is tender, turn off heat, remove lid, and stir in Swiss chard.
Replace lid and allow chard to wilt for 5–10 minutes.