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

In a small mug or bowl, mix the flax seeds with 1 tablespoon of cold water and set aside for 5 minutes. It will end up thick and gloopy. This is your flax 'egg', which will help to bind the cookies together.

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

Add in all of the flour. Stir until the mixture starts to stick to itself, then use your hands to press it into a large ball of dough. If the dough is sticky, you can add more flour. If it's too dry, add a splash of plant-based milk.

Add the chocolate chunks and the crushed chocolate eggs. Press them into the dough using your hands.

Divide the dough into 12 equal-sized pieces and roll into balls. Place them onto your baking tray and gently flatten them until they're around 1-inch thick. Make sure to leave 2-3 inches of space between them as they will spread a lot.

Bake the cookies for 12 minutes and let them cool completely before removing them from the tray.