Add the frozen bananas, berries, beets, almond milk, and ice cubes to a high-speed blender. Cover and blend on the highest setting until completely smooth and creamy, approximately 2 minutes. If necessary, add a little water to reach the desired consistency if the mixture is too thick.
Divide between 4 glasses or mason jars and top each serving with some chia seeds. Garnish each glass or jar with a sprig of fresh mint, if using, and serve immediately. Enjoy!
Note: Raw or roasted beets can be used in this recipe. However, roasted beets will yield a smoother texture. To save time on busy mornings, wash and wrap the beets in aluminum foil and toss into a hot oven for approximately 1 hour while making dinner throughout the week. Store roasted beets in the refrigerator for several days until ready to use. You can substitute water for almond milk for a brighter red color and fewer calories.