Mousse: whisk the milk and mousse mix with an electric mixer for 2 mins on low, followed by 5 mins on high.
Cherries: heat the sugar and vinegar together until it turns a light caramel colour. Reduce the heat and add the star anise, cinnamon and cherries. Cover and warm through on low for 5 mins. Cool and keep chilled.
Cream: whisk the cream and vanilla to soft peaks. Sift in the icing sugar and fold through.
To assemble: cut the brownies into small cubes and place at the base of each dessert glass. Top with a few cherries and juice. Pipe or spoon the chocolate mousse on top and follow with a quenelle or piped chantilly cream. Garnish with a couple of sour cherries.