Step 1: Preheat your oven to 350°F. Line a 9x13-inch baking pan with parchment paper. Melt the butter and chocolate chips together in a microwave-safe bowl. Stir in the sugar, then add eggs and vanilla. Sift in flour, cocoa powder, and salt, then fold together. Pour into the pan and bake for 20-25 minutes. Let cool completely.

Step 2: Prepare the cookie dough by creaming together softened butter, brown sugar, and granulated sugar. Add egg and vanilla, then mix. In a separate bowl, whisk together flour, baking soda, and salt. Gradually add dry ingredients to wet ingredients, then fold in chocolate chips. Press into another lined 9x13-inch pan and bake at 350°F for 15-18 minutes. Let cool completely.

Step 3: Beat softened cream cheese until smooth. Add powdered sugar and vanilla, mixing until incorporated. Whip heavy cream until stiff peaks form, then fold into the cream cheese mixture.

Step 4: Assemble the dessert by layering the brownie layer, half of the cheesecake filling, the cookie layer, and the remaining cheesecake filling. Refrigerate for at least 4 hours.

Step 5: Before serving, top with whipped cream and garnish with chocolate shavings or mini chocolate chips.