Preheat the oven to 350°F and coat an 8x8 or 9x9 baking dish with non-stick baking spray.
Make the cheesecake filling: In a medium bowl, use an electric mixer to beat the cream cheese, egg, vanilla, and powdered sugar together until smooth and creamy.
Build the base: Divide the sugar cookie dough in half. Press half into the bottom of your prepared pan to form an even layer.
Add the filling: Pour the cheesecake mixture over the cookie dough base and spread it evenly to the edges.
Top it off: Flatten small pieces of the remaining cookie dough into discs and arrange them over the cheesecake filling, covering as much of the surface as possible.
Bake for 30–35 minutes, or until the top begins to turn a light golden brown. Let cool completely before adding sprinkles, slicing, and serving.