1tablespoonground flaxseedyou can also use chia seeds
28gunflavored whey proteinvanilla is another great option. If it's presweetened you can skip the extra stevia.
Place all ingredients into a blender or Vitamix and blend until smooth.
Freezing banana for smoothies - I love having frozen bananas on hand for smoothies. To freeze fresh bananas, place whole, peeled bananas on a parchment-lined baking sheet. Set in the freezer until frozen solid. Then, transfer the frozen bananas to a freezer-safe resealable bag and freeze for up to 6 months.
Use fresh & frozen fruit - Some of each makes it easier to blend.