2 1/4 cups all-purpose flour
2 1/2 teaspoons sifted baking powder
1/2 teaspoon salt
3/4 cup butter
1/2 cup granulated white sugar
2 cups dark brown sugar (spoon lightly into cup)
3 whole eggs
1 teaspoon pure vanilla extract
1. Preheat the oven to 350degF. Line an 8"x12"x2.5" pan with aluminum foil and set aside.
2. In a bowl, combine flour, baking powder and salt. Set aside.
3. Cream the butter and sugar until light and fluffy. Add the white and brown sugar and beat until blended. Add the eggs and vanilla and mix well.
4. Mix the flour using a rubber scraper. Beat until combined only. Do not overmix.
5. Transfer the batter to the prepared pan and bake for 45-55 minutes until toothpick inserted in all four corners come out dry. Do not wait for the center of the cookie to test clean.
6. Cool then cut into squares.