Preheat the oven to 180ºc / 350ºf / Gas 4. Line 2 baking trays with grease proof paper.
Melt the butter and honey together in a pan over a low heat, then cool for 5 mins.
In a small bowl, mix the bicarbonate of soda with 1 tbsp. cold water then add to the butter mixture.
In a large bowl, combine the oats, flour, both sugars and coconut together. Stir in the butter mixture and add the beaten egg and mix well.
Drop teaspoons of the mixture onto the baking sheets, spaced well apart to allow for spreading and flatten slightly.
Bake in the oven for 20mins or until crisp and golden. Leave on the baking sheet to firm, then transfer to a wire rack to cool.