Chocolate Chip Cookie Bars Recipe

Ingredients (13)

• 2 1/4 cups ( 305 g) all-purpose flour
• 1 tablespoon ( 9 g) cornstarch
• 1 teaspoon ( 6 g) baking soda
• 1 teaspoon ( 6 g) kosher salt
• 1/2 teaspoon ( 2g) baking powder
• 1 cup ( 226 g) unsalted butter , melted and cooled to room temperature
• 1 cup ( 215 g) packed light brown sugar
• 1/2 cup ( 99) g granulated sugar
• 1 1/2 teaspoons vanilla extract
• 2 large eggs , at room temperature
• 1 egg yolk , at room temperature
• 2 cups ( 240 g) chopped semi-sweet chocolate or chocolate chips
• 1 cup ( 110 g) chopped walnuts , optional