3 cups whole milk
1 vanilla bean, split lengthwise
¾ cup large egg yolks (about 10 yolks)
¾ cup plus 2 tablespoons sugar, plus extra as needed
2 cups peaches
1½ cups heavy cream
Pinch salt
Recipe
Freeze the empty container in which you plan to store the finished ice cream.
Heat the milk and vanilla bean in a heavy, nonreactive saucepan over medium heat, until the mixture is steamy and hot, with tiny bubbles forming at the pan's edge. Don't let it boil. Remove the pan from the heat and cover.
With an electric mixer, whip the yolks and sugar until they are pale yellow and silky looking. The mixture should stiffen up enough to hold its shape. With the mixer running, or whisking briskly by hand, add the hot milk slowly, in a thin stream, mixing the whole time. Add all of the milk (vanilla bean included).
Prepare an ice water bath in a bowl large enough to surround the top half of a double boiler. Use lots of ice cubes and about 1 quart of water.
Prepare a double boiler and cook the milk mixture in the top of it over medium heat, stirring constantly until the mixture thickens. To test it, remove the pan from the heat and coat the back of a wooden spoon with the mixture; if a line drawn through the coating holds its shape, the custard is thick enough (185°F on an instant-read thermometer). Do not cook it beyond this point or the custard will curdle. Move the top of the double boiler over to rest in the ice water bath, stirring the custard to cool it down as quickly as possible. When the mixture is very cold, it can be refrigerated in a tightly sealed container to further develop the flavors overnight, or it can be made up immediately as follows.
Peel the peaches (see page 97), cut them open, and remove the stones. Purée 1 cup of the peaches and dice 1 more cup of fresh peaches quite small. Refrigerate until needed.
Before pouring the ice cream custard into the machine, remove the vanilla bean and scrape the seeds into the custard. Add the cream, salt, and the peach purée and mix well. Pour the ice cream custard into the ice cream machine and mix it for 15 to 20 minutes, until it's the consistency of soft-serve ice cream. (Be careful: Overmixing can churn your cream into butter—there will be little flecks of it everywhere if this happens.)
Swirl the chopped peaches into the partially frozen ice cream and quickly fill the prechilled container with the ice cream, using a spatula to compress it. Cover the container and thwack it down on the counter a few times to get the air bubbles out. Place a layer of waxed paper directly on top of the surface of the ice cream and cover it tightly with the lid of the container. Allow the ice cream to set up in the freezer for at least 4 hours before serving.
Ice cream is best served within a couple of days. For the best-tasting ice cream flavors, ice cream is ideally served softened a bit. To achieve the proper consistency, take hard ice cream from the freezer and temper it in the refrigerator for 20 to 30 minutes before serving.