Step 1

Combine ground flax and soy milk in a large mixing bowl and set aside for 15 minutes.

Step 2

Preheat the oven to 180° C / 355° and line two baking trays with baking paper.

Step 3

Place broken up chocolate bar and butter in a metal or glass bowl suspended over a water bath. Set the heat to very low and make sure the bowl does not touch the water underneath. Allow the contents of the bowl to melt gently without stirring.

Step 4

Add both sugars to the thickened flax mixture and whisk with an electric whisk for 2 minutes, until thick and a bit paler.

Step 5

Gently stir melted chocolate and vegan butter together until well combined, then pour it into the flax and sugar mixture while whisking.

Step 6

Fold in flour, salt, baking soda and cocoa powder in two batches. Stir well to combine.

Step 7

Drop about 3 tbsp worth of batter (scant ¼ cup) per cookie on two trays, 5 cookies on each.

Step 8

Bake for 8 minutes, then take each tray out, bang the tray until the countertop gently so that the cookies crack and spread a little and return to the oven for another 2 minutes.

Step 9

Allow the cookies to cool off completely before prising them off gently with a spatula. Store in an air-tight container.