Place the strawberries and blueberries into the blender, layering the berries separately to facilitate layering later.
1 cup strawberries, 1 cup blueberries
Add the peeled banana, vanilla yogurt, and milk into the blender over the berries.
1 banana ripe banana, 1 cup vanilla yogurt, 0.5 cup milk
Secure the lid on the blender and blend on high speed for 30-45 seconds until the mixture is smooth and creamy, with no lumps visible.
Pour the red layer (strawberry mixture) into the glasses, filling about half the glass to create the red section.
Rinse the blender quickly, then blend the blueberry mixture until smooth. Pour the white layer (blueberry smoothie) gently over the back of a spoon onto the red layer to create a layered effect.
Optional: Use a skewer or toothpick to swirl lightly through the layers for a marbled or patriotic effect. Serve immediately with a straw.
