In a food processor, mix bananas, 1 cup milk, orange peel, honey, and vanilla extract until pureed, about 2 minutes.
Pour mixture into a deep saucepan. Whisk in remaining 2 cups milk. Bring to a boil over medium-high heat, whisking regularly. Reduce heat to simmer. In a small bowl, stir cornstarch into water until dissolved. Whisk into banana mixture. Continue heating and whisking until the mixture thickens, about 5 minutes. Pour into a large bowl and cover. Refrigerate 2 hours or overnight.
To serve, ladle 1-1/3 cups banana mixture into a dessert dish or bowl. Using a vegetable peeler, shave a bit of the chocolate on top to garnish.