Cut corn off the cobs and set aside.
Place cobs in a large pot and barely cover with water. Bring to a boil, then lower the heat and simmer for about an hour. Strain the stock and set aside.
Reserve one cup of the corn kernels and place the remaining corn in a blender. Blend, starting on low speed and increasing to high as the corn purees, for about 1 minute.
Pour the corn through a fine-mesh strainer into a medium saucepan. Add the thyme and cook over medium heat, stirring frequently without allowing the soup to boil. Gradually add the lemon juice and the reserved corn stock; cook until the soup thickens. You should have 4 to 6 cups. Add salt to taste.
Heat a small frying pan over medium heat; add enough olive oil to film the bottom of the pan. When the oil begins to smoke, add the reserved corn kernels and do not stir until the corn has a nice brown color. Stir the corn and then remove it from the heat. Place the seared corn and any other grilled vegetables of your choice on top of the soup and serve.