Pumpkin Chocolate Chip Cookie Bars

Bahan-bahan (20 porsi)

• 2 1/2 cups flour
• 1 tablespoon pumpkin pie spice
• 1 tablespoon cornstarch
• 1 teaspoon baking soda
• 1 teaspoon salt
• 1 cup (2 sticks) butter, melted
• 1 cup light brown sugar
• 1/2 cup granulated sugar
• 1/2 cup pumpkin puree
• 1 teaspoon vanilla extract
• 1 cup chocolate chips, plus more to top