4 large peaches (about 1 1/2 pounds)
1 1/2 tablespoons freshly squeezed lemon juice
3/4 cup plus sugar, divided
2 tablespoons peach schnapps
2 cups milk
2 cups heavy cream
1 (4-inch) piece vanilla bean, split lengthwise
6 large egg yolks
Custard base used in this recipe can be prepared up to 48 hours ahead. If you plan to make ice cream on same day as custard mixture, proceed with preparing peach puree. If you plan to prepare custard mixture ahead but not freeze it until following day, don't make peach puree until several hours before that.
To prepare the peaches, bring a medium saucepan of water to a boil; have ready an ice-water bath. Place peaches in boiling water and cook for 1 to 2 minutes. Transfer peaches to ice-water bath using a slotted spoon and let them cool. Peel, pit and slice peaches. Place peaches in a nonreactive pot with the lemon juice and 2 tablespoons of the sugar. Cook mixture over medium to medium-high heat, stirring occasionally, until peaches are very tender and juice has thickened slightly, which should take about 7 to 10 minutes.
Scrape peaches and juice into bowl of a food processor or blender, add the peach schnapps and puree until very smooth. Scrape puree into a bowl, cover with plastic wrap, pressing down against the surface to keep the surface from being exposed to air, and refrigerate until thoroughly chilled.
To prepare custard, in a medium, heavy-bottomed saucepan, combine the milk, cream and remaining sugar. Scrape seeds from the vanilla bean into pan and add pod to pan. Heat mixture just until it begins to steam and bubble around edges, then remove from heat.
Whisk the egg yolks in a medium bowl. Whisk 1 cup hot cream into egg yolks. Gradually whisk egg-and-cream mixture back into pan. Cook over medium-low heat, stirring occasionally to allow for even cooking and to avoid scorching until mixture thickens enough to lightly coat back of a spoon and custard reaches 170 F on an instant-read thermometer. Remove from heat and gently pour into a clean bowl sitting in an ice bath and cool, stirring occasionally so a skin doesn't form.
When custard has cooled for about 20 minutes, remove from ice bath, cover with plastic wrap, pressing down against the surface to keep a skin from forming, and refrigerate until thoroughly chilled, at least 2 hours but up to 48 hours is OK.
When ready to make ice cream, remove custard from refrigerator, stir in peach puree and pour mixture into bowl of an ice-cream machine. Freeze according to manufacturer instructions.
Makes about 1 quart.