Preheat oven to 325°F. Line an 8x8 inch baking pan with foil or parchment paper, leaving an overhang on two sides. Lightly grease with cooking spray.

In a medium bowl, combine graham cracker crumbs, melted butter, 1/4 cup brown sugar, 1/4 teaspoon cinnamon, and salt. Mix until evenly moistened.

Press the crumb mixture firmly into the bottom of the prepared pan. Bake for 10-12 minutes until edges are lightly golden. Set aside to cool.

Beat cream cheese and granulated sugar together until smooth and fluffy, about 2 minutes. Add eggs one at a time, mixing well after each addition.

Stir in vanilla extract and sour cream until fully combined. Do not overmix.

In a small bowl, combine 1 cup brown sugar, flour, and 2-3 tablespoons cinnamon. Pour in 6 tablespoons melted butter and stir until thick and paste-like.

Spread half of the cheesecake filling over the cooled crust. Dollop half of the cinnamon mixture on top and swirl gently with a knife.

Repeat with remaining cheesecake filling and cinnamon mixture. Swirl in a figure-eight pattern to create marbled layers.

Bake for 35-40 minutes. Edges should be set but center should still have a slight jiggle. Do not overbake.

Cool completely in the pan on a wire rack. Refrigerate for at least 2 hours or overnight before slicing.

Use the foil overhang to lift bars out of the pan. Cut into 16 squares using a sharp knife dipped in hot water between cuts.