Ingredients
1 cup sugar (220 g)
1/3 cup (75 g) butter, softened
1 large egg
½ cup (55 g) all-purpose flour (- perhaps a little more)
½ cup (50 g) unsweetened cocoa powder
½ teaspoon baking soda
1 teaspoon vanilla extract
6 oz (170 g) semisweet chocolate chips