Preheat your oven to 200°C/400°F (or 180°C/350°F if you're using a fan or convection oven). Line a large baking tray or two with baking paper or have a non-stick cookie sheet to hand.

In a small mug or bowl, mix the ground flax seeds with 1 tablespoon of cold water. Set it aside for around 5 minutes. It will become thick and gelatinous, and will act as your egg replacement.

In a large bowl, mix the margarine, brown sugar and caster sugar together. Then stir in the flax seed mixture and the vanilla extract.

Add all of the flour to the bowl. Stir it with a spoon until it starts to stick together, then use your hands to press it into a ball of dough.

Add the chocolate chips and gently fold them in using your hands.

Divide the dough into 8 equal-sized pieces. Roll each piece into a ball then flatten to around ½ an inch thick.

Place the discs of cookie dough onto your tray(s), leaving a few inches of space between them to allow for spreading.

Bake for 12 minutes. Leave them on the tray until they are completely cool. They will be fragile when they come out but firm up as the cool.