2 cups plus 2 tbsp All- purpose flour
1 tsp Baking soda
1/2 tsp Salt
1 1/4 cups (21/2 sticks) Unsalted butter, softened
2 cups Granulated sugar
3 Large eggs
21/2 tsp Pure vanilla extract
8 oz Cream cheese, softened
1/2 cup Confectioner’s sugar, sifted
Vegetable oil cooking spray
1. Coat a 9-by-13 inch baking dish with cooking spray. Line the dish with parchment,leaving a 2-inch overhang along the sides, then spray the parchment.
2. Into a large bowl, sift together flour, cocoa powder, baking soda and salt. With an electric mixer on medium-high speed, cream the butter and granulated sugar until smooth. Add 2 eggs and 2 tsp of vanilla, and continue beating, scraping down the sides of the bowl as needed. Reduce the speed of the mixture to low, gradually add the flour mixture. Increase the speed to medium;beat until incorporated.
3. Preheat oven to 325 degrees. Reserve 1 cup of dough; cover and refrigerate. Press remaining dough into the bottom of the prepared dish. Chill for 30 minutes. Bake until the base is set and the edges are puffed for about 25 minutes. Transfer dish to a wire rack to cool completely.
4. Mix cream cheese, confectioner’s sugar and remaining egg and 1/2 tsp of vanilla extract in a medium bowl. Spread over cooled base. Using a pastry bag fitted with a large plain tip, pipe reserved dough on top. (Let it soften slightly if it is too hard to pipe.) Starting at one corner and working in even intervals across, pipe diagonal lines perpendicular to the first set.
5. Bake until the filling sets, about 25-30 minutes. Let it cool in the dish over a wire rack, then use an overhang to lift it out. Trim the edges. Cut into 20 bars (11/2 by 21/2 inches.) The bars can be refrigerated up-to 3 days in airtight containers.