Cream the Sugars and Butter: In a large bowl or the bowl of a stand mixer, combine the slightly cooled melted butter with the soft light brown sugar and granulated sugar. Whisk or beat on a medium speed for about 2 minutes until the mixture is well combined and has a wet sand-like texture.

Add the Eggs and Flavourings: Add the whole egg and the egg yolk and beat again for another minute until the mixture is lighter in colour and texture. Whisk in the vanilla and peppermint extracts. If you're using green food colouring, add a few drops now and mix until you have a pale minty green colour.

Combine Dry Ingredients: In a separate bowl, whisk together the plain flour, bicarbonate of soda, baking powder, and salt. This ensures the leavening agents are evenly distributed.

Mix Dough: Gently fold the dry ingredients into the wet ingredients using a spatula or on a low mixer speed. Be careful not to overmix; stop as soon as the last streaks of flour disappear. Overmixing can lead to tough cookies.

Stir in Chocolate: Pour in the dark chocolate chips and stir them through the dough until they are evenly distributed.

Chill the Dough: This step is critical! Cover the bowl with cling film and place it in the refrigerator to chill for at least 1 hour, or up to 3 days. The dough will become firm.

Preheat and Prep: When you’re ready to bake, preheat your oven to 180°C (160°C fan). Line two large baking trays with parchment paper.

Scoop and Bake: Using a medium ice cream scoop or two spoons, portion out balls of dough (around 2 tablespoons each). Place them on the prepared trays, leaving about 5-6cm of space between each one to allow for spreading. I find that an ice cream scoop is the best tool for uniform, round cookies.

Bake to Perfection: Bake for 10-12 minutes. The cookies are done when the edges are set and lightly golden, but the centres still look slightly soft and underdone. They will continue to cook on the hot tray.

Cool Down: Remove the trays from the oven. For those lovely crinkled tops, you can gently bang the tray on your work surface once or twice. Let the cookies cool on the baking tray for 5-10 minutes before transferring them to a wire rack to cool completely.