If using an ice cream maker with a removable canister, be sure to freeze the canister at least one day before you plan to make ice cream. Also note that the ice cream mixture needs time to chill before churning (at least an hour), and the churned ice cream needs about 3 to 4 hours in the freezer for a firmer, scoopable consistency.
Make the ice cream:
In a small sauce pan, simmer oats in 1 cup of milk until soft, about 10 minutes. Immediately transfer to a bowl or spread out on a plate to cool.
In a blender combine the remaining 2 cups of milk and the pistachios. Blend on high until completely smooth, about 1 minute. Add the cooled oatmeal, sugar, vanilla, salt, and vodka, if using. Blend again until smooth and oats are fully broken down. Refrigerate until cold (minimum 2 hours), or to speed up the process, transfer ice cream mixture to a container and place in freezer for about 30 minutes.
Churn the ice cream according to manufacturer's instructions for your machine. After churning, the ice cream will be softer than a typical soft serve consistency. For a firmer, scoopable consistency, transfer ice cream to a freezer-safe container, cover, and freeze for 3 to 4 hours.
Around the 4 hour mark, and definitely once the ice cream has been in the freezer longer, it will be too hard to scoop right out of the freezer. It's important to let the ice cream soften at room temperature for about 15 minutes before serving.
Alcohol:Since alcohol doesn't freeze, adding it to homemade ice cream recipes is a common trick to help keep the ice cream a bit softer straight from the freezer. Since my oat ice cream recipes don't contain added oils, gums, or sugar syrups like store-bought ones, a small amount of alcohol can help with texture, but feel free to omit it. Storage and Serving:Store ice cream in an airtight container in the freezer. It tastes best when consumed within 1 week only because it can be difficult to fully protect it from air.Always allow about 15 minutes for the ice cream to soften before serving.Nutrition facts are estimates.