Pumpkin Chocolate Chip Bars

2 cups all-purpose flour (spooned and leveled)
1 tablespoon pumpkin-pie spice
1 teaspoon baking soda
3/4 teaspoon salt
1 cup (2 sticks) unsalted butter, room temperature
1 1/4 cups sugar
1 large egg
2 teaspoons vanilla extract
1 cup canned pumpkin puree
1 package (12 ounces) semisweet chocolate chips

Preheat oven to 350 degrees. Line bottom and sides of a 9-by-13-inch baking pan with foil, leaving an overhang on all sides. In a medium bowl, whisk together flour, pie spice, baking soda, and salt; set aside.

With an electric mixer, cream butter and sugar on medium-high speed until smooth; beat in egg and vanilla until combined. Beat in pumpkin puree (mixture may appear curdled). Reduce speed to low, and mix in dry ingredients until just combined. Fold in chocolate chips.

Spread batter evenly in prepared pan. Bake until edges begin to pull away from sides of pan and a toothpick inserted in center comes out with just a few moist crumbs attached, 35 to 40 minutes. Cool completely in pan.

Lift cake from pan (using foil as an aid). Peel off foil, and use a serrated knife to cut into 24 squares. (I've never tried the foil trick until now - it worked great!)

Recipe courtesy of Martha Stewart. The recipe does not call for frosting, but I added the below Cream Cheese Frosting to half the pan and I loved them with the frosting.

Cream Cheese Frosting:

8 ounces cream cheese, softened
3-4 cups confectioners' sugar
4 tablespoons unsalted butter, softened
1 1/2 teaspoon vanilla
1/2 teaspoon lemon zest (optional)