Holding the end of the corn slice the kernels off each ear to yield 4-5 cups of kernels. Cut or break 2 of the cobs into 2-3″ pieces, keeping kernels and cobs separate. Discard remaining cobs. Set aside.

Slice bottom inch off lemon grass and discard. Cut a 3″ piece off the bottom, discard top. Peel and discard firm outer layers of stalk until the inside is exposed. Finely slice the inside portion.

Combine chopped cobs (NOT the kernels), with coconut milk, stock, lemongrass, and ginger in stock pot over high heat. Bring to a boil. Reduce heat and simmer for 10 minutes. Remove from heat, discard cobs, and allow to cool.

Meanwhile, heat oil in a medium sauce pan over medium heat. Add shallots and cook for 2 minutes. Add corn kernels and cook until tender 8-10 minutes. Season with salt and pepper. Remove from heat.

Combine half of coconut milk mixture with half the kernels mixture in a blender. Purée until smooth. Pour through a fine mesh sieve into a large bowl. Repeat with remaining corn and coconut milk mixtures.

Stir in fish sauce, 2 tbsp basil, and 1/2 cup of crab meat into soup. If soup is too thick add more stock.

Refrigerate until cold, 2 to 3 hours. Taste and add more salt and pepper is desired.

To serve place additional crab meat in shallow bowls, top with soup, basil (garnish), and chili oil if desired.