Add the juice to a blender pitcher, then the add the yogurt.
Add frozen pineapple and banana over top of the yogurt.
Blend for 45 seconds on medium-high speed. Keep pulsing the blender until smooth.
Pour into two glasses. Top with fresh pineapple and a pinch of granola if desired.
Notes
We love using unsweetened coconut yogurt for this (it tastes like a piña colada!) but unsweetened/plain yogurt will work too. You can use fresh or frozen fruit, but if using fresh you will need to add 1 cup of ice to get the smoothie super cold. Add more pineapple juice if your blender gets stuck, or wait a few minutes for the frozen fruit to thaw a little bit.