Preheat your oven to 350°F (175°C) and line an 8"x8" baking dish with parchment paper for easy removal.

In a mixing bowl, combine graham cracker crumbs, granulated sugar, and melted butter until the mixture resembles wet sand. Firmly press this mixture into the bottom of the prepared baking dish, creating an even layer. Bake the crust for 8-10 minutes until lightly golden and fragrant.

In an electric mixer, combine softened cream cheese, sour cream, brown sugar, and granulated sugar. Beat on medium speed until smooth and fluffy. Blend in pure vanilla extract, pumpkin purée, and pumpkin pie spice until well incorporated. Gently add the eggs, mixing just until combined.

Once the filling is ready, pour it over the pre-baked crust, spreading it evenly with a spatula. Bake in the preheated oven for 30-35 minutes, or until the edges are set but the center is still slightly jiggly.

After baking, remove the pan from the oven and let it cool completely at room temperature. Once cooled, cover the baking dish with plastic wrap and refrigerate for several hours or overnight.

Just before serving, whip the heavy cream in a mixing bowl until it begins to thicken. Add powdered sugar and ground cinnamon while continuing to whip until stiff peaks form.

Once the topping is in place, it's time to slice the Pumpkin Cheesecake Bars. Use a sharp knife, wiping it clean between cuts for neat slices. Serve chilled.