Step 1

Make the custard: Whisk the corn, half-and-half, sour cream, sugar and vanilla in a medium saucepan and bring to a simmer over medium heat. Lightly beat the egg yolks in a medium bowl. Slowly whisk about 1/4 cup of the warm corn mixture into the beaten egg yolks, then pour into the saucepan and return to medium heat. Cook, stirring constantly with a wooden spoon, until the mixture thickens and coats the spoon, about 5 minutes.

Step 2

Transfer the hot custard to a blender and pulse until smooth (keep the filler cap slightly open to let steam escape). Strain the custard through a fine-mesh sieve into a large bowl; discard the solids. Stir often until the mixture cools to room temperature. Lightly press plastic wrap directly against the surface of the custard to prevent a skin from forming. Chill until cold, about 3 hours. (For faster chilling, set the bowl of custard in a bowl of ice water and stir until cold.)

Step 3

Freeze the cold custard in an ice cream maker according to the manufacturer's directions. Transfer to an airtight container and freeze until firm, 2 to 3 hours.

Step 4

Scoop the ice cream into bowls. Top with caramel corn or a splash of bourbon, if desired.