Add all ingredients to your blender.
Blend on high for 30-45 seconds, or until completely smooth. Add more liquid as needed to reach your desired texture. Taste your smoothie -- if you aren't using protein powder, you may wish to add another banana half for sweetness.
The smoothie will thicken as it sits, so enjoy immediately.
Vanilla protein powder will add sweetness to this smoothie. If you leave it out, you may wish to use a full banana for extra sweetness.
Nutrition facts calculated without protein powder or milk.
Calories: 377kcal, Carbohydrates: 44g, Protein: 19g, Fat: 16g, Saturated Fat: 4g, Polyunsaturated Fat: 5g, Monounsaturated Fat: 5g, Trans Fat: 0.02g, Cholesterol: 7mg, Sodium: 59mg, Potassium: 435mg, Fiber: 10g, Sugar: 20g, Vitamin A: 145IU, Vitamin C: 7mg, Calcium: 235mg, Iron: 2mg