Prepare the mix for your Ninja CREAMI: Mix all the ingredients - the skim milk, vanilla protein powder, vanilla extract, and the whole can of the root beer. Blend until smooth with your immersion blender.
Chill the Mixture: Place the mixture in the refrigerator to chill for about 18-24 hours. I usually just put it in the freezer overnight.
Assemble the Ninja CREAMI: Once the freezer bowl is frozen and the mixture is chilled, assemble the Ninja CREAMI machine according to the manufacturer's instructions.
Run your Ninja CREAMI: Make your ice cream in your Ninja CREAMI. I used the Lite Ice Cream setting (has 4 cycles). I ran it again on mix it 2 more times until it was smooth.
Serve and Enjoy: Serve immediately and enjoy your Ninja CREAMI Vanilla Root Beer Float Protein Ice Cream!