Make the sweet potato puree by peeling the sweet potato and chopping into chunks. Boil until tender, around 20 minutes. Mash with a fork or for a smoother texture use a blender. Set aside to cool, or put in the fridge to cool faster
Put the finely chopped dried dates into a bowl and cover with the boiling water. Set aside to cool, the dates will soak up the water and plump up
Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4 and grease and line 8 inch square tin
Melt the coconut oil in a pan on a low heat. In a bowl whisk together the coconut oil with the maple syrup
Then whisk in the eggs and vanilla extract
Whisk or stir in the sweet potato puree and the date and water mixture
Whisk in the plain flour, baking powder and cocoa powder
Pour the mixture into the tin, try and level out the top as much as you can, and bake for 30 minutes
Leave to cool fully. Melt the dark chocolate and drizzle all over the brownies to decorate
Store in the fridge for 5 days, or you can freeze them and defrost as needed