In a mixing bowl, combine graham cracker crumbs, granulated sugar, and melted unsalted butter until the mixture resembles wet sand. Firmly press the crumb mixture into the bottom of a 9-inch springform pan to create a solid crust. Bake at 325°F for 10 minutes or until lightly golden. Allow to cool completely.

Using an electric mixer, beat the cream cheese in a large bowl until silky smooth. Gradually add brown sugar and vanilla extract, mixing until fully incorporated. Add the eggs one at a time, mixing gently, then fold in pumpkin puree and pumpkin pie spice until just combined.

Pour the creamy filling over the cooled crust in the springform pan. Bake at 325°F for 50-55 minutes, or until the edges look set and the center has a slight jiggle. Allow to cool in the pan for a few minutes before cooling further.

After removing from the oven, crack the door and let cool gradually for 1 hour. Transfer to room temperature, then refrigerate for at least 4 hours or overnight.

In a saucepan over medium heat, combine chopped pecans, brown sugar, heavy cream, and butter. Stir continuously for 3-5 minutes until the mixture begins to boil and sugar dissolves. Allow to cool slightly before pouring over the cheesecake.

Let the praline topping set on the cheesecake before slicing with a long, hot knife. Serve chilled, optionally with whipped cream or cinnamon.