Coconut milk and Asian herbs and spices transform everyday corn chowder into an entirely new taste experience. This soup can be served with shrimp or lobster instead of crab, and it's even good without any shellfish at all.
If you don't have time to make the corn stock, substitute vegetable or chicken stock.
Remove the kernels of corn from the cobs with a sharp knife and set aside. Place the cobs in 4 cups of water and bring to a simmer over high heat. Reduce the heat to medium and cook until the liquid has reduced to 1-1/2 cups.
Meanwhile, place a large saucepan over medium heat and add the oil. When the oil is hot, add the onion and cook, stirring frequently, until the onion has softened, about 10 minutes. Add the garlic, lemongrass, ginger, and jalapeño and cook, stirring frequently, for another 2 minutes.
Add the potatoes, coconut milk, cumin, and the corn stock to the saucepan and bring to a boil over high heat. Reduce the heat to medium and simmer the chowder until the potatoes are tender, about 20 minutes.
Add the crabmeat and cook until just heated through, about 3 minutes. Add the lime juice to taste. Ladle into bowl and garnish each serving with a sprinkling of cilantro. Serve hot.