Pre-heat oven to 180ºC.
Add oats, flaxseed, coconut, finely chopped walnuts, baking powder, cinnamon and carrots to a bowl and stir well.
Mix in the maple syrup, rapeseed oil, lemon zest and peanut butter until it is fully combined.
Line two loaf tins with a little parchment paper, divide the mixture between the tins and press down hard using the spoon’s back.
Bake for 25 minutes, then remove from the oven and leave to cool fully before icing.
To make the icing, stir the yoghurt, icing sugar and about a quarter of the lemon juice together. Add more lemon juice to get the sauce to a spreadable consistency, then leave it in the fridge until ready to serve.
Cut the bars, then spoon the icing into a piping bag and drizzle over the top.
Store in an airtight container in the fridge.