1. Using an electric whisk, cream the butter and sugar together in a bowl for 2-3 minutes until very pale and fluffy. Creaming incorporates air into the mixture making a lighter cookie.
2. Stir together flour, baking powder and sea-salt; set aside.
3. Stir in the egg and vanilla extract into the butter mixture followed by flour; beat together until the mixture forms a soft dough. Fold in chocolate chunks or chips until well incorporated.
4. Make ping-pong sized balls with cookie dough and chill for 30 minutes. Chilling the dough will help the cookies retain their shape while baking. 
5. Preheat your oven to 180˚C. Arrange chilled cookie dough balls on a baking sheet, leaving 3-4 cm of space in between cookies as they spread while baking.
6. Bake for about 11-12 minutes until golden at the bottom. Leave the cookies to cool for about 5 minutes on the baking sheet, then transfer to a wire rack to cool. Enjoy them warm or store in an airtight container for up to 5 days.
7. Cover any leftover balls of cookie dough in plastic wrap to freeze for later use. Cookie dough can be frozen for up to three months. To use, simply thaw in the refrigerator for a few hours before baking. Enjoy fresh cookies whenever you please :)