For the crust:
1½ cups graham cracker crumbs (from about 8 whole graham crackers)
5 tablespoons unsalted butter, melted
For the cookie dough:
5 tablespoons butter, melted and cooled
1/3 cup light brown sugar
¼ cup all-purpose flour
½ teaspoon vanilla extract
¾ cup semisweet chocolate chips
For the cheesecake filling:
10 ounces cream cheese, at room temperature
¼ cup granulated sugar
1 teaspoon vanilla extract
For the chocolate drizzle:
1/3 cup semisweet chocolate chips
1 teaspoon vegetable shortening
1. Preheat oven to 325 degrees F. Lightly grease an 8x8-inch baking pan, line with parchment paper, and butter the parchment paper; set aside.
2. Stir together the graham cracker crumbs and melted butter until the crumbs are evenly moistened. Press the crumb mixture into the bottom of the pan. Bake for 6 minutes or until lightly browned. Cool on a wire rack.
3. To make the cookie dough, stir together the butter and sugar until smooth. Stir in the flour, then the vanilla and chocolate chips. Refrigerate until firm (about 30 minutes), and then roll teaspoon-sized ball of the dough and place on a plate, and refrigerate plate of cookie dough balls while you prepare the cheesecake filling.
4. Beat together the cream cheese and sugar on medium speed until smooth, scraping the bowl as needed. Add the egg and vanilla extract, beating until thoroughly combined.
5. Remove the cookie dough balls from the refrigerator and toss with 1 teaspoon of flour. Drop into the cheesecake filling and mix together. Pour the filling into the cooled crust, coaxing the filling into corners and sides. Bake for about 30 minutes, or until the cheesecake filling is set and doesn't jiggle. Transfer to a wire rack to cool completely. Chill in the refrigerator for at least 2 hours.
6. Using the parchment paper as handles, lift the bars out of the pan and place on a cutting board. Cut into squares. Combine the chocolate chips and shortening in a small bowl and microwave for 1 minute at 50% power and stir until smooth. Drizzle over the bars and allow to set for about 20 minutes. Store leftovers in the refrigerator.