Mix the ground flax seeds with 1 tablespoon of water and leave for a few minutes until thick and gloopy.

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

Add the self-raising flour and press everything together into a ball of dough. Gently press in the chocolate chips.

Divide the dough into 10 equal pieces and roll into balls. Gently flatten them to make discs that are roughly 1 inch thick.

Line the air fryer tray with baking paper and preheat to 180℃ for 5 minutes. I recommend using the standard air fry setting, not the bake setting.

Cook the cookies in batches of 2 or 3 for 8-9 minutes, until they're firm around the edges. They will look a little underbaked at first but will crisp up and brown more while they're cooling.

Carefully remove the cookies from the fryer using the baking paper. Sprinkle with sea salt and let them cool until they're firm enough to lift off of the paper.

Repeat until all of the cookies are baked, or store any leftover dough in the fridge for up to 3 days.