Sprinkle the gelatin over the cold water in a small bowl and let soak for 5 minutes.
Using a sharp knife, carefully cut kernels off the ears of corn. Add kernels to a food processor or blender along with the milk. Process until corn is rendered into small pieces. .
Pour into a saucepan along with heavy cream. Heat corn and liquid mixture just to a simmer, stirring occasionally; do not let it boil. Remove from heat, and allow to steep for 10 minutes
Once mixture has steeped, pour it through a fine-mesh strainer into a clean saucepan; discard kernel pulp. Add sugar, and heat mixture over medium just to a simmer once again, stirring to dissolve sugar. Meanwhile, microwave the gelatin on high for about 15 seconds or until melted.
Once the milk mixture has come to a simmer, remove it from the heat. Whisk in the gelatin until fully incorporated and the mixture is smooth. Add sour cream, whisking until fully incorporated and smooth. Pour into 4 ramekins or custard cups. Chill for at least 2 hours, until set.
Top with Glazed Nuts, Candied Bacon, or Blueberry Sauce, if desired.