Add the milk, pineapple juice, and protein powder to a Ninja® CREAMi® jar. Froth until smooth. Cover and freeze overnight.
Add the jar to the Ninja® CREAMi® Ice Cream Maker and spin on 'Lite Ice Cream.' Remove and add two tablespoons of milk. Return to the Ninja® CREAMi® Ice Cream Maker and spin on 'Re-Spin.'
Split into two servings, top with fresh pineapple and enjoy!
