Preheat the oven to 180C/350F/gas mark 4. Grease a 20cm/8inch square tin and line with baking parchment.
Mix together the ground flaxseed and the water in a small bowl, set aside to go gloopy.
Whisk together the plain flour, bicarbonate of soda, cinnamon, ginger, nutmeg, cloves, allspice and salt in a large bowl with a balloon whisk and set aside.
Place the chopped dark chocolate in a heatproof bowl along with the coconut oil, cocoa powder, red wine and instant espresso powder.
Remove the bowl from the heat and add the sugar, orange zest and the flaxseed mixture. Whisk with an electric mixer until it is smooth and glossy.
Spoon the batter into the prepared tin and use a spatula to spread it level. It won't spread much in the oven so make sure you get it as level as you can.
Bake for 22-25 minutes until a skewer inserted near the edge comes out with moist crumbs on it. The middle should still be a little gooey.
Leave to cool in the tin for about an hour then carefully lift the slab out and slice into squares.