The next day, preheat an oven to 175°c/155°c fan (350°f/311°f).
Place 3-4 balls of cookie dough onto a lined baking tray, making sure that there’s plenty of room between them.
Bake the cookies for 10 minutes then open your oven door, lift up the baking tray inside the oven by a few inches then let it drop down against the oven rack. Use enough force so that the cookie starts to deflate. (This is the “Pan Banging” method.)
Bake for a further 2 minutes then repeat the pan banging process.
Bake for another 2 minutes (bringing the total bake time to 14 minutes) then remove from the oven. Once baked, the cookies' edges will be golden brown but the middles will still be soft. Using a large, round cookie cutter, gently scoot each cookie into a perfect round shape.
Sprinkle each cookie lightly with sea salt then leave on the tray, to cool completely.
Repeat the cooking process with the remaining cookies, baking 3-4 cookies at a time.