01 - Preheat oven to 325°F. Grease and line the bottom of a 9-inch springform pan with parchment paper.
02 - Mix crushed chocolate sandwich cookies with melted butter until evenly moistened. Press firmly into the bottom of the prepared pan. Place in the freezer while preparing the next layers.
03 - In a mixing bowl, beat softened butter with brown sugar and granulated sugar until light and creamy. Mix in milk and vanilla extract. Add heat-treated flour and salt; combine just until a dough forms. Fold in mini chocolate chips. Shape most of the dough into small marble-sized balls, reserving some for topping. Refrigerate dough balls until ready to use.
04 - In a large bowl, beat softened cream cheese with granulated sugar until smooth. Add eggs one at a time, beating well after each addition. Blend in sour cream, vanilla extract, and all-purpose flour, mixing until just incorporated.
05 - Pour half of the cheesecake batter over the frozen cookie crust. Evenly distribute half the cookie dough balls over the batter. Gently spread the remaining cheesecake batter on top, smoothing the surface. Optionally, arrange reserved cookie dough balls on the surface.
06 - Bake for 55 to 65 minutes, until edges are set and the center is slightly wobbly. Turn off oven, crack the door open, and let cheesecake cool inside the oven for 1 hour.
07 - Remove from oven and allow cheesecake to cool fully at room temperature. Transfer to the refrigerator and chill for at least 4 hours or overnight for best results.
08 - Before serving, garnish with mini chocolate chips and extra cookie dough balls if desired. Slice with a large, sharp knife and serve chilled.