- In a large bowl, whisk the white granulated sugar, light brown sugar and melted butter until smooth.
- Add the egg and the vanilla extract and whisk until light and creamy.
- Sift the flour, baking powder, baking soda and sea salt into the bowl then fold the mixture with a wooden spoon or spatula. Be careful not to overmix the cookie dough; overmixing causes gluten development, which makes for cakey (rather than chewy) cookies. The dough will be soft but thick.
- Fold the chocolate into the mixture. Cover and chill the cookie dough for at least 30 mins, or preferably, a couple of hours (or even overnight). Chilling is mandatory! The longer the dough rests, the more complex its flavour will be and the less it’ll spread as it bakes, which makes for a deliciously chewy cookie.
- Heat oven to 180℃/ 160℃ fan. Line two large baking trays with greaseproof paper.
- Form the dough into balls, about 1 heaped tablespoon of dough each. Arrange the cookies in a single layer on both baking sheets, leaving plenty of space for the cookies to spread.
- Bake for 13 to 15 minutes, or until the edges have just started to brown. The cookies will look a little soft, but don’t worry - they will continue to bake on the baking tray.
- Let the cookies cool on the baking sheet for 10 minutes, then transfer them to a wire rack to cool completely.
- Here’s the hardest part: wait for the cookies cool completely then serve. Enjoy!