01 - Preheat oven to 325°F. Grease and line the base of a 9-inch springform pan.
02 - Combine crushed chocolate sandwich cookies with melted butter until evenly moistened. Press mixture firmly into the bottom of the prepared pan to form an even layer. Freeze while assembling remaining components.
03 - In a mixing bowl, beat together softened butter, brown sugar, and granulated sugar until pale and fluffy. Incorporate milk and vanilla. Add heat-treated flour and salt, mixing just until combined. Fold in mini chocolate chips. Shape most of the dough into marble-sized balls, reserving some dough for topping if desired. Chill the dough balls until firm.
04 - Beat softened cream cheese and granulated sugar in a large bowl until completely smooth. Add eggs one at a time, mixing thoroughly after each. Blend in sour cream, vanilla, and flour just until mixture is cohesive.
05 - Pour half of the cheesecake batter onto the chilled cookie crust. Distribute half the cookie dough balls evenly over the batter. Pour the remaining cheesecake mixture over the top and smooth with a spatula. Arrange remaining cookie dough balls on the surface for the decorative effect if desired.
06 - Bake for 55 to 65 minutes, or until the edges are set and the center appears slightly jiggly. Switch off the oven, crack the oven door, and allow the cheesecake to cool in the oven for 1 hour.
07 - Remove cheesecake from oven and let cool completely at room temperature. Refrigerate for at least 4 hours or overnight for optimal texture.
08 - Prior to serving, garnish with additional mini chocolate chips and reserved cookie dough balls if desired. Slice and serve chilled.