Preheat your oven to 325°F (163°C). Line a 9x13‑inch baking pan with parchment paper, leaving overhang on the long sides for easy lifting. Lightly spray the parchment and sides with nonstick spray.

In a medium bowl, combine the graham cracker crumbs, 1/4 cup granulated sugar, 1/2 teaspoon ground cinnamon, and 1/8 teaspoon fine sea salt. Pour in the 1/2 cup melted butter and stir until the crumbs are evenly moistened and the mixture holds together when pressed.

Pour the crust mixture into the prepared pan. Press it firmly into an even layer, all the way to the edges and corners, using your hands or the bottom of a measuring cup. Bake for 8–10 minutes, until lightly set and fragrant. Remove from the oven and let cool slightly while you prepare the filling.

In a large mixing bowl or stand mixer fitted with the paddle attachment, beat the softened cream cheese on medium speed for 2–3 minutes until very smooth and creamy. Scrape down the sides and bottom of the bowl. Add 3/4 cup granulated sugar and the light brown sugar, then beat for 1–2 minutes more until well combined and fluffy.

Add the eggs one at a time, beating on low speed just until each is incorporated. Add the sour cream, vanilla extract, 1 1/2 teaspoons ground cinnamon, and 1/8 teaspoon fine sea salt. Mix on low until the batter is smooth and silky with no streaks, avoiding overmixing.

Give the par‑baked crust a quick check to be sure it is even, then pour the cinnamon cheesecake filling over the warm crust. Smooth the top with an offset spatula or the back of a spoon. Gently tap the pan on the counter a few times to release any large air bubbles.

Bake at 325°F (163°C) for 30–38 minutes, depending on your oven. The edges should look set, while the center should still have a slight jiggle, like firm Jell‑O. If you see large cracks forming, it is likely done. Avoid overbaking so the bars stay creamy.

Turn off the oven and crack the door open a few inches. Let the cheesecake bars sit in the oven for 15 minutes. Then transfer the pan to a cooling rack and cool completely to room temperature. This gentle cooling helps prevent cracking and keeps the texture smooth.

In a small bowl, stir together 1/4 cup granulated sugar and 1 1/2 teaspoons ground cinnamon for the topping. When the cheesecake is just warm (not hot), brush the top lightly with the 2 tablespoons melted butter, then sprinkle the cinnamon sugar evenly over the surface so it adheres.

Cover the pan and refrigerate the bars for at least 4 hours, or overnight for best texture and flavor. When ready to serve, use the parchment overhang to lift the slab out onto a cutting board. With a long, sharp knife, wiping it clean between cuts, slice into 16–20 bars.

Serve the churro cheesecake bars plain or with warm caramel sauce, whipped cream, extra cinnamon sugar, and crushed graham crackers if desired. For parties, keep the bars chilled until about 20 minutes before serving so they stay firm but not too cold.