Add all ingredients except brandy to the blender. Blend until smooth. Pour into saucepan and gently heat, whisking constantly until it reaches a simmer and thickens. Remove from heat, let cool for 30 minutes and add in brandy. Blend with an immersion blender. Pour into a jug and place into the fridge to chill for a few hours until completely cold. Stir or shake before serving. Top with a sprinkle of cinnamon. Serves 5.