Process the beetroot on a powerful blender with a little bit of water.
Heat oven to 180°C/160°C fan/gas Spread coconut oil, then line a 20 x 30cm traybake or small roasting tin.
Roughly chop the chocolate and melt it with the coconut oil in a low heat.
Put the molasses and eggs into a large bowl, then beat using an electric hand whisk until thick, pale and foamy, about 2 mins. Spoon the beetroot mix into the bbwl. Add the blueberries in the mix.
Add the melt chocolate and coconut oil.
Sift in the flour and cocoa powder, then gently fold these in to make a smooth batter.
Pour into the prepared tin and bake for 25 mins or until risen all over, with just the merest quiver under the centre of the crust when you shake the pan. Cool completely in the tin, then cut into squares.