Preheat your oven to 180°C/350°F (or 160°C/325°F if you're using a fan or convection oven). Have a non-stick cookie sheet to hand or line a tray with baking paper.

Mix the ground flax seeds with 1 tablespoon of cold water and set aside to thicken. This will act as your egg replacement.

In a large bowl, mix together the margarine, brown sugar and caster sugar until smooth.

Mix in the flax seed mixture and the vanilla extract.

Add the flour, cocoa powder and baking soda. Mix it all in with a spoon until the mixture starts to stick to itself. Then use your hands to press it into a ball of dough. Press the chocolate chips into the dough.

Divide the dough up into 8 equal-sized pieces and roll each piece into a ball. Place them onto your tray and use your fingers to flatten them to around ½ an inch thick. They will spread out slightly while baking so make sure to leave an inch or two of space between each one.

Bake for 15 minutes and leave them on the tray until completely cool before enjoying.