Add all of the ingredients except the stout and cream to a shaker with ice, then shake vigorously. Strain into a glass over ice. Top with stout, making sure to pour off the ice so it mixes. Layer cacao cream on top and garnish with chocolate shavings.
Cinnamon SyrupBlend together 8 oz. simple syrup and 2 cinnamon sticks. Fine strain the cinnamon bits out.
Cacao CreamAdd 4 oz. of heavy cream, 1/4 to 1/2 oz. crème de cacao (depending on its sweetness), and a pinch of sea salt to a shaker. Shake until the whipped cream can hold its shape.
