Nans Secret The Ultimate Soft Chewy Sugar Cookies

Ingredients

• 1 cup (2 sticks) unsalted butter, softened (227g)
• ¾ cup granulated sugar (150g)
• ¾ cup packed light brown sugar (150g)
• 2 large eggs
• 2 teaspoons vanilla extract (10ml)
• 2 ¼ cups all-purpose flour (281g)
• 1 teaspoon baking soda (5g)
• 1 teaspoon cream of tartar (3g)
• ½ teaspoon salt (3g)
• 2 tablespoons cornstarch (16g)
• Extra granulated sugar (for rolling, optional)