Add the frozen mango, pineapple, banana, yogurt, protein powder, lime juice, and chia or flax to a high-powered blender.
Pour in 1/3 cup milk to start. You want as little liquid as possible for a thick bowl.
Blend on low, then increase speed, using a tamper to push the fruit toward the blades.
If it struggles, add 1 to 2 tablespoons more milk at a time.
Blend until smooth and soft-serve thick. It should mound on a spoon and not run.
Taste and adjust: add more lime for brightness or a tiny drizzle of honey if needed.
Spoon into a bowl and add your favorite toppings. Think crunchy granola, juicy fruit, and a sprinkle of seeds.