Blend the base: Add the cottage cheese, milk, pistachio butter, allulose, protein powder, and almond extract to a high-speed blender and blend until completely smooth with no visible curds. Add food coloring if using.
Churn the ice cream: Pour the mixture into your ice cream maker and process according to maker's instructions. I used the Ninja CREAMi, which requires freezing until the mixture is solid before processing. I processed on the lite ice cream setting.
Add pistachios: Stir in the chopped pistachios after churning, or use them as a topping when serving. You can also add them and use the "mix in" cycle on the Ninja Creami if you want them fully mixed in.
