2 and 1/4 cups (280g) all-purpose flour (spoon & leveled) 1 teaspoon baking soda 1 and 1/2 teaspoons cornstarch* 1/2 teaspoon salt 3/4 cup (1.5 sticks or 170g) unsalted butter, melted & slightly cooled* 3/4 cup (150g) packed light or dark brown sugar 1/2 cup (100g) granulated sugar 1 large egg + 1 egg yolk, at room temperature 2 teaspoons pure vanilla extract 1 and 1/4 cups (225g) semi-sweet chocolate chips or chocolate chunks
