Preheat your oven to 350°F (175°C). Lightly grease a 9×13-inch baking pan or line it with parchment paper, leaving an overhang on the long sides to create handles for easy removal.

In a medium bowl, combine the graham cracker crumbs, 1/4 cup granulated sugar, 1 teaspoon ground cinnamon, and a pinch of fine sea salt. Pour in the 1/2 cup melted butter and mix until all the crumbs are evenly moistened and the mixture resembles wet sand. If it looks too dry, add up to 1 more tablespoon melted butter.

Transfer the crumb mixture to the prepared pan. Use the bottom of a measuring cup or a clean glass to press the crumbs firmly into an even layer, going slightly up the sides if desired. Bake for 8–10 minutes, until the crust looks set and smells toasty. Set aside to cool slightly while you prepare the filling.

In a large mixing bowl, beat the softened cream cheese with a hand mixer or stand mixer fitted with the paddle attachment on medium speed for 2–3 minutes, until very smooth and free of lumps. Scrape down the sides of the bowl once or twice.

Add 2/3 cup granulated sugar to the cream cheese and beat for about 1 minute, until combined and slightly fluffy. Add the eggs one at a time, mixing on low to medium speed after each addition just until incorporated and you no longer see streaks of egg. Avoid overmixing to keep from incorporating too much air.

Add the sour cream or Greek yogurt, vanilla extract, 1 1/2 teaspoons ground cinnamon, flour, and a pinch of salt. Beat on low speed until the mixture is smooth and uniform, scraping down the bowl as needed. The batter should be pourable but not runny.

In a small bowl, stir together 1/4 cup granulated sugar and 1 1/2 teaspoons ground cinnamon. Set aside. For extra depth, you can add a tiny pinch of nutmeg if desired.

Check that the crust has cooled slightly and is no longer very hot. Pour the cinnamon cheesecake filling over the crust and gently spread it into an even layer with an offset spatula or the back of a spoon. Tap the pan on the counter a few times to release any large air bubbles.

If using, lightly brush or drizzle the 2 tablespoons melted butter over the surface of the filling for extra churro flavor. Sprinkle the cinnamon sugar mixture evenly over the top of the filling. It may look like a lot, but it will bake into the cheesecake and form a sweet, crackly top.

Bake at 350°F (175°C) for 25–30 minutes. The edges should look set, and the center should still have a slight jiggle when you gently shake the pan. If the top starts to brown too quickly, tent the pan loosely with foil near the end of baking. Remember, the cheesecake will continue to set as it cools.

Turn off the oven and crack the door open a couple of inches. Let the pan sit in the oven for about 10 minutes. Then transfer the pan to a wire rack and let it cool completely to room temperature. This gentle cooling helps minimize cracking, though the cinnamon sugar topping hides most small cracks.

Cover the cooled pan tightly with foil or plastic wrap and refrigerate for at least 3 hours, or overnight for best texture and flavor. Chilling allows the bars to set fully and slice cleanly.

Use the parchment overhang to lift the chilled churro cheesecake slab out of the pan and onto a cutting board. Slice into about 16 large bars or up to 24 smaller bars, wiping your knife with a warm, damp cloth between cuts for clean edges. Serve as is or garnish with warm caramel sauce, whipped cream, fresh berries, and a sprinkle of extra cinnamon sugar.