Combine all ingredients except the blueberries in an airtight container or jar with a lid. Seal container and shake vigorously for a minute or so until everything is well incorporated and no lumps appear. Note that you may prefer less or more maple syrup depending on how sweet your protein powder is.
Place sealed container in the fridge for 45 minutes or ideally overnight.
Remove from fridge, stir and pour over ½ cup of frozen blueberries. Allow at least 5 minutes for the blueberries to thaw before eating. You could also add the blueberries in the night before if you'd prefer.