Shuck the corn and with a sharp knife, trim the kernels from the cobs and reserve. Cut each cob into 3 pieces and place in a medium saucepot. Add the water and 2 teaspoons salt to the pot and bring the mixture to a boil; reduce the heat to simmer and cook 30 minutes to create a corn broth. Strain the liquid into a clean bowl and place next to the stove. Discard the boiled cobs, rinse the pot and place back on the stove over a medium flame.
Melt the butter in the pot; add the reserved corn kernels, the scallions, garlic and 1 teaspoon of salt. Cook the vegetables until tender and very aromatic but not browned, about 7 minutes. Scoop 1 cup of corn broth from the bowl and add to the vegetables; continue cooking until all of the liquid has evaporated. Add the remaining corn broth into the vegetables and simmer 15 minutes more. Transfer the mixture to a blender and process until smooth.
Set a fine mesh strainer over a clean bowl. Pour the pureed soup through the strainer and press the solids with the back of a spoon to extract as much of the liquid as possible. Place the corn puree in the refrigerator to cool. Just be fore serving, whisk in the sour cream and adjust the seasoning to taste with salt and pepper.
Divide into bowls and garnish with shrimp and roasted tomatoes.
Recipe by The Couple's Kitchen at https://thecoupleskitchen.com/chilled-sweet-corn-soup-w-roasted-cherry-tomatoes-avocado-grilled-shrimp/