Boil the kettle. Heat the oven to 170C/150C fan/gas 3 1/2, butter a 20 x 30cm cake tin and line with baking parchment. Tip the dates into a heatproof bowl and cover with 60ml boiling water from the kettle. Set aside to rehydrate for 10 mins, then tip into a food processor and blitz until smooth.

Melt the butter and honey in a saucepan over a low heat, stirring until smooth. Tip the carrots, oats, cranberries, apricots, chopped walnuts, mixed seeds, mixed spice, cinnamon and a small pinch of salt into a large bowl. Stir the sweetened butter and puréed dates into the dry ingredients until combined, then tip into the prepared tin and press into an even layer using a spatula. Bake for 45-50 mins, covering with foil halfway through if the flapjacks brown too quickly. Cool in the tin. Once completely cool, chill in the fridge for at least 3 hrs.

For the icing, whisk all of the ingredients together until smooth. Drizzle the icing over the flapjacks and cut into 12 bars. Will keep, covered in the fridge, for three days.