Preheat the oven to 180°C/160°C Fan/Gas 4. Line a large cooking tin with baking parchment. The recommended size is 30 x 20cm - although I use a larger one and just pack it into the corner!
Put the butter, honey and dates into a saucepan over a low heat. Melt them together, crushing the dates with a spoon so they break up into the butter and honey.
Stir in the oats and coconut and mix thoroughly.
Pack the mixture in the prepare tin and bake for 20-25 minutes until golden brown. The flapjacks will still seem soft at this point, but don't worry - they'll firm up once cool.
Remove the tin from the oven and immediately score the surface into about 15 squares. Leave the flapjack to cool in the tin, then cut into squares.