Prepare the cookie dough layer by creaming together brown sugar and softened butter until light and fluffy. Add egg and vanilla extract, mix well. In a separate bowl, whisk together flour, baking soda, and salt, then gradually add to wet ingredients until just combined. Set aside.

Make the cheesecake filling by beating cream cheese and granulated sugar until smooth. Add eggs one at a time, mixing well after each. Stir in vanilla extract. In another bowl, whisk together flour, baking soda, and salt, then gradually add to cream cheese mixture. Fold in mini chocolate chips.

Assemble the bars by pressing the graham cracker crust mixture into the bottom of a greased and lined 9x9-inch baking pan. Spread cheesecake filling evenly over the crust, then drop spoonfuls of cookie dough over the cheesecake layer and swirl slightly.

Preheat oven to 325°F. Bake assembled bars for 30-35 minutes until edges are set and center is slightly jiggly. Let cool at room temperature, then refrigerate for at least 2 hours before slicing.