In a blender, combine the peaches, banana, milk, yogurt, honey, cinnamon, and ginger, if using. Blend on low to break up the peaches, stopping to scrape down the sides of the blender, as needed. Increase the speed to high and blend until very smooth, about 20 seconds. Taste and add additional honey, if desired. Divide between 2 glasses and garnish each with a peach slice.