This recipe is straight out of the New York Times, which has a special feature this week featuring sweet corn recipes.
Heat 4 T. butter in a heavy pot. Dice 1 onion and add the pot, cooking over low heat for 10 minutes.
Add 2 minced cloves of garlic, 1 T. minced fresh ginger, and 1/2 t. each turmeric, cumin seeds, and mustard seeds. Add a good pinch of cayenne if you want it spicy. Stir and cook with the onions for 2-3 minutes.
Shuck 4 ears of corn and cut the kernels off the cobs. Add the corn to the pot and cook for a few minutes to combine with the onions. Add 4 C. of water and bring to a boil, then simmer for 10 minutes.
Puree the soup in a blender then return to the pot and season with salt and pepper.
Ladle the soup into bowls and stir 2 T. creamy plain yogurt into each bowl. Serve with cilantro sprigs and lime wedges.