01 - Preheat oven to 325°F (160°C). Lightly grease and line the bottom of a 9-inch (23 cm) springform pan.
02 - Combine crushed chocolate sandwich cookies with melted butter in a bowl. Mix until thoroughly blended. Firmly press the mixture into the bottom of the prepared springform pan. Freeze the crust while you prepare the remaining components.
03 - In a mixing bowl, cream softened butter with brown sugar and granulated sugar until light and fluffy. Add milk and vanilla extract, and mix to combine. Gently mix in heat-treated flour and salt until just incorporated. Fold in mini chocolate chips. Roll most of the dough into small marble-sized balls, reserving some dough for topping if desired. Refrigerate cookie dough balls until ready to use.
04 - Beat softened cream cheese with granulated sugar until smooth and free of lumps. Add eggs one at a time, mixing well after each addition. Blend in sour cream, vanilla extract, and all-purpose flour, mixing until just combined.
05 - Pour half of the cheesecake batter over the prepared crust. Scatter half of the cookie dough balls evenly onto the batter. Pour the remaining cheesecake batter over and smooth the surface. Arrange the rest of the cookie dough balls on top for garnish if desired.
06 - Bake in the preheated oven for 55 to 65 minutes, or until the edges are set and the center jiggles slightly. Turn off the oven, crack the oven door, and let the cheesecake cool inside for 1 hour.
07 - Remove cheesecake from the oven and cool to room temperature. Transfer to the refrigerator and chill for at least 4 hours or ideally overnight. Before serving, sprinkle mini chocolate chips and any reserved cookie dough balls over the top. Slice and serve chilled.