Makes about 24
½ cup unsalted butter, at room temperature
½ cup castor sugar
½ cup packed brown sugar
1 large egg
1 teaspoon vanilla extract
1¼ cups all-purpose flour
½ teaspoon baking soda
¼ teaspoon salt
1½ cups dark cooking chocolate
fine sea salt flakes for topping
1 Place rack in the upper third of the oven and preheat oven to 180C.
2 Line two baking sheets with baking paper.
3 Carefully melt half a cup of the cooking chocolate.