Wash and peel the beetroot, then chop it into small cubes. Peel the banana and prepare the remaining ingredients.
Pour the almond milk and Greek yogurt into the blender first.
Add the chopped beetroot, banana, mixed berries, chia seeds (if using), honey or maple syrup (if desired), and ice cubes.
Blend on high speed for 45–60 seconds until completely smooth and creamy.
Taste the smoothie and adjust the sweetness by adding a little more honey or maple syrup if needed. Blend again for a few seconds.
Pour into chilled glasses or mason jars, garnish with fresh berries or chia seeds if desired, and enjoy immediately.