2. Bring the milk to a simmer in a large saucepan. Add the corn kernels and cobs, remove from the heat, cover, and let steep for 45 minutes.
3. Remove the corncobs from the milk and discard. Use an immersion blender to buzz the milk and corn to break up the kernels; or transfer the milk and corn to a regular blender, in batches, and blend to break up the kernels. Strain through a coarse strainer into a bowl (discard the remaining corn mush). Measure the milk and add more if necessary to make 3 1/2 cups.
4. Combine the milk, cream, and 1 1/4 cups of the sugar in a large heavy-bottomed sauce- pan and bring just to a simmer over medium heat, stirring to dissolve the sugar.
5. Meanwhile, whisk the egg yolks, the remaining 1/4 cup sugar, and the salt together in a medium heatproof bowl. Gradually whisk in 1 cup of the hot milk mixture, then return the mixture to the saucepan and cook over medium heat, stir- ring constantly with a heatproof spatula or a wooden spoon, until the custard registers 185°F on an instant-read thermometer.
6. Immediately strain the custard through a fine-mesh strainer into a heatproof bowl and chill over an ice bath, stirring occasionally, until cold. Cover and refrigerate for at least 6 hours, or, preferably, overnight.
7. Freeze the gelato in an ice cream maker according to the manufacturer's instructions. Pack into a freezer container and freeze for at least 1 hour before serving. (The gelato is best served the day it is made.)
Excerpted with permission from Molto Italiano: 327 Simple Italian Recipes to Cook at Home by Mario Batali. © 2010, Ecco. From the July 31, 2010 show.
Andrea Reusing is the creator of the restaurant Lantern in Chapel Hill, N.C., and author of the book Cooking in the Moment: A Year of Seasonal Recipes. In this installment of The Key 3, she shares with Lynne Rossetto Kasper the techniques behind three of her favorite recipes: Turnip Soup, Overnight Braised Short Ribs and Tomato Salad.