Peel the mango, cut the flesh into thin slices and arrange in a fan shape on serving plates. Drizzle with orange liqueur.
Heat the butter for the brittle. Sprinkle the sugar evenly over the top. When it is runny and light brown, add the desiccated coconut and roast while stirring until light brown. Put on a plate and let cool down.
To serve, sprinkle the coconut brittle over the mango slices.