4 ears sweet corn, shucked
2 cups whole milk
2 cups heavy cream
3/4 cup granulated sugar, divided
1 teaspoons coarse salt
9 large egg yolks
Carefully cut kernels from the corncobs and transfer kernels to a saucepan. Break cobs in half and add to saucepan. Stir in the milk, cream, 1/2 cup of the sugar and the salt. Bring mixture to a boil; let cool and discard cobs.
Working in batches, puree corn mixture in a blender until smooth. (For safety, remove cap from hole in lid and cover with a dish towel to prevent spattering.) Return mixture to saucepan and bring to a simmer over medium heat. Remove from heat.
Meanwhile, prepare an ice-water bath. Whisk together the egg yolks and remaining 1/4 cup sugar in a small bowl. Whisk 1 cup corn mixture into yolks, then return entire mixture to saucepan, whisking constantly. Cook over medium-low heat, whisking constantly, until custard thickens and can easily coat back of a spoon, about 10 minutes.
Strain custard through a fine sieve into a bowl, pressing down on solids; discard solids. Transfer bowl to ice-water bath and refrigerate for 1 hour.
Freeze mixture in an ice-cream maker according to manufacturer's instructions. Transfer to an airtight container and freeze until firm, at least 3 hours. Ice cream will keep, frozen, for up to 3 months.
— Recipe from the July 2011 issue of Martha Stewart Living magazine.