Add the frozen raspberries, sliced banana, plain yogurt, cold milk, honey, vanilla extract, and ice cubes to a blender.
Blend on low speed to begin breaking up the frozen raspberries and ice, then increase to high speed and blend until very smooth and creamy, 45–60 seconds. Stop and scrape down the sides of the blender as needed.
Check the consistency. If the raspberry smoothie is too thick, blend in a little more milk, 1–2 tablespoons at a time. If it is too thin, add a few more frozen raspberries or ice cubes and blend again until smooth.
Taste and adjust the sweetness with a little more honey if desired, blending briefly to combine.
Pour the raspberry smoothie into two glasses and top with fresh raspberries for serving. Serve immediately while cold and thick.