Preheat Oven:
Preheat your oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper or lightly grease it.

Prepare the Sugar Cookie Crust:
If using store-bought dough, press the dough evenly into the bottom of the prepared baking pan. If using homemade dough, mix the dough with 1/4 cup of flour and press it evenly into the bottom of the pan to form a crust. Use your fingers or the back of a spoon to flatten the dough into an even layer.

Bake the Crust:
Bake the sugar cookie crust for 10-12 minutes, or until it’s lightly golden and set. Remove from the oven and let it cool slightly while you prepare the cheesecake filling.

Make the Cheesecake Filling:
In a large mixing bowl, beat the softened cream cheese with the granulated sugar until smooth and creamy. Add the vanilla extract and mix until combined. Add the eggs, one at a time, mixing well after each addition. Stir in the sour cream (if using) and flour until smooth.

Assemble the Bars:
Pour the cheesecake mixture over the cooled sugar cookie crust, spreading it evenly. Make sure the filling covers the entire surface of the crust.

Bake:
Bake for 30-35 minutes, or until the cheesecake is set and the edges are lightly golden. The center should be slightly jiggly but not runny. If a toothpick is inserted into the center, it should come out mostly clean with just a few crumbs attached.

Cool:
Let the bars cool to room temperature in the pan, then refrigerate for at least 2 hours (or overnight) to allow the cheesecake to firm up and set completely.

Top with Sugar:
Before serving, sprinkle the top of the bars with a light dusting of granulated sugar for a little extra sweetness.

Serve:
Slice into squares and serve chilled. Enjoy the perfect combination of sugar cookie and cheesecake!