Cut 6 cups worth of kernels from ears of corn; scrape the milk-like stuff and remaining pulp from cobs using the dull side of a kitchen knife.

Heat oil in a large saucepan over medium flame, then add onions, thyme, and 1/4 teaspoon salt. Turn the heat down to medium-low and cover. Cook for 8 minutes or until the onion is softened while giving an occasional stir. Add the corn kernels and garlic and re-cover. Cook 4 minutes; add corn pulp, water and remaining 1/2 teaspoon salt. Increase heat to medium-high and bring it to a boil. 

Remove the saucepan from the heat and ditch the thyme. Place half of the corn mixture in a blender. Remove center piece of blender lid (this'll let the steam escape); secure blender lid on blender. Place a clean towel over opening in blender lid (this'll prevent splattering). Blend until smooth. Strain corn mixture through a sieve into a large bowl and ditch and solids that come out. Repeat procedure with remaining corn mixture. Let it chill in the fridge for at least 4 hours.

Combine remaining ingredients in a small bowl. Ladle 1 cup soup into each of the 6 bowls and finish them off by topping with 2 tablespoons avocado mixture.