This is a fresh summer soup, flecked with bacon and whole kernels of sweet corn. The recipe makes use of the scraped corn cobs by simmering them in water to make a light broth, which is then used in the soup in place of chicken broth. I find this extra step really amps up the corn flavor. The basil-chili oil adds a peppy splash of green. —Merrill Stubbs
Using a sharp knife, cut the corn kernels from the cobs and set aside. (You should have about 6 cups of corn kernels.) Put the corn cobs in a large saucepan and cover them with 2 quarts of water. Bring to a boil over high heat, then lower the heat and simmer gently for about 15 minutes.
In a large pot, cook the bacon over medium heat for about 5 minutes, until it has rendered most of its fat and is crispy. Add the onion, a large pinch of salt and pepper to taste and cook until the onion is translucent, 3 to 5 minutes. Add the corn kernels, stir through and cook for another minute.
Carefully strain the corn cob cooking liquid through a fine mesh sieve and add 6 cups to the corn mixture, reserving the rest. Bring to a boil over high heat, then lower the heat and simmer for 15 to 20 minutes so that the flavors have a chance to meld. (Do not overcook -- the kernels should still have a bit of a bite.)
Meanwhile, to make the basil-chili oil, blanch the basil leaves in boiling water for about 30 seconds, drain and plunge into a bowl of ice water. (This is a bit of a pain, but if you don't do it, your "basil-chili oil" will end up looking like gray sludge.) Remove and dry thoroughly. Combine the basil leaves, olive oil, a sprinkling of salt and the chili flakes in a blender and purée until smooth. Transfer to a small bowl, cover and set aside until ready to use it will be better after an hour or two.
Starting with a clean blender and working in small batches so you don't burn yourself, purée about 3/4 of the corn soup until smooth. Combine with the remaining soup, taste and add more salt and pepper if necessary. Transfer the soup to a large bowl and refrigerate until icy cold (you may also eat it hot if you prefer). Serve the soup in individual bowls with a generous drizzle of the basil chili-oil.