Preheat the oven to 180 C / Gas 4. Cover 2 baking trays with greaseproof paper.
Beat the egg whites until stiff and shiny, incorporating the icing sugar little by little. Fold in the flour and the coconut.
Drop small spoonfuls of the mixture onto the prepared baking trays, leaving space in between so they can spread without touching.
Bake in the preheated oven until lightly golden, about 15 minutes. Remove and cool completely on a wire rack.
Melt the chocolate in a small bowl over warm water. Using a pastry brush, coat the bottom of each macaroon with the melted chocolate. Place with the bottom up on a wire rack and let rest for 1 to 2 hours before eating.