6 Giant Chocolate Chip Cookies

and 1/4 cups (280g) all-purpose flour (spoon & leveled)

and 1/2 teaspoons cornstarch

teaspoon baking soda

teaspoon salt

or 170g) unsalted butter, softened to room temperature

packed light or dark brown sugar

(100g) granulated sugar

large egg + 1 egg yolk, at room temperature

teaspoons pure vanilla extract

and 1/2 cups (270g) semi-sweet chocolate chips (plus extra for tops, if desired)