Combine Dry Ingredients: In a medium bowl, whisk together the plain flour, cocoa powder, bicarbonate of soda, and salt. Set this aside.

Cream Butter and Sugars: In a separate large bowl, using an electric mixer or a stand mixer with the paddle attachment, beat the room-temperature butter with the light brown sugar and caster sugar on medium speed for about 2-3 minutes, until the mixture is light, pale, and fluffy.

Add Wet Ingredients: Add the egg and vanilla extract to the butter mixture and beat again for another minute until well combined. Scrape down the sides of the bowl to ensure everything is incorporated.

Mix Dough: Gradually add the dry ingredients to the wet ingredients in two or three batches, mixing on a low speed until just combined. Be careful not to overmix at this stage.

Fold in Chocolate and Chill: Gently fold in the dark chocolate chips using a spatula. The dough will be quite soft. Cover the bowl with cling film and place it in the refrigerator to chill for at least 30 minutes.

Prepare the Cookie Balls: Once chilled, preheat your oven to 180°C (160°C fan) and line two large baking trays with baking parchment. Scoop out a portion of dough (about 1.5 tablespoons) and flatten it into a disc in your palm. Place one soft caramel in the centre.

Stuff and Roll: Carefully wrap the dough around the caramel, pinching the seams to seal it completely. Roll it gently between your palms to form a smooth ball. What works best for me is ensuring there are no cracks where the caramel could escape.

Arrange and Sprinkle: Place the dough balls onto the prepared baking trays, leaving at least 5-7cm of space between each one to allow for spreading. Sprinkle the top of each cookie ball with a generous pinch of flaky sea salt.

Bake to Perfection: Bake for 10-12 minutes. The cookies will look slightly puffed up and the edges will be set, but the centres will still be very soft. They might look underdone, but they will continue to cook on the tray.

Cool and Enjoy: Remove the trays from the oven and let the cookies cool on the baking trays for 5-10 minutes. This is vital as it allows them to set. Afterwards, transfer them to a wire rack to cool completely. They are best enjoyed warm when the caramel is extra gooey.