I love alcohol-flavored gelato because the alcohol cuts the richness of the dairy and also allows the gelato to get super-cold. But because alcohol doesn’t freeze, if you add too much to the gelato it won’t freeze at all. After making many versions with varying amounts of booze, we determined that the recipe below contains the maximum amount of alcohol that will freeze in a home ice cream maker. If it’s still not boozy enough for you, do as I do: Drizzle a few drops of bourbon over the top.
Fill a large bowl with ice water and set a smaller bowl inside.
Set a fine-mesh strainer in the smaller bowl. Whisk the cornstarch and 1 cup of the milk together in a medium-sized bowl until the cornstarch dissolves. Combine the sugar, milk powder, corn syrup, salt, and the remaining 3 cups of milk in a 4-quart saucepan over high heat. Whisk to break up and dissolve the milk powder, and heat the milk until it just begins to bubble. Turn off the heat and gradually add the milk and cornstarch mixture, whisking constantly. Return the heat to high and bring the milk back to a boil.
Reduce the heat to medium-high and cook, stirring constantly with the whisk, until the gelato base thickens slightly, 4-5 minutes. It will get viscous but will not thicken enough to coat the back of a spoon.
Pour the gelato base through the strainer into the bowl set over the ice water and set aside to cool to room temperature. Transfer the base to an airtight container and refrigerate for at least several hours and up to 3 days.
Remove the base from the refrigerator, pour it into a large bowl, and stir in the cream and bourbon. Pour the base into the bowl of an ice cream or gelato maker and spin it according to the machine instructions.
Serve the gelato straight from the maker or transfer it to an airtight container and place it in the freezer until you’re ready to serve it.
Serve the gelato within a few hours of spinning it, before it hardens.