Preheat the oven to 350°F (175°C). In a mixing bowl, combine graham cracker crumbs, chopped toasted pecans, and sugar. Pour in the melted butter and stir until the mixture resembles damp crumbs. Press this mixture firmly into the bottom of a springform pan to form an even crust. Bake in the preheated oven for 8-10 minutes until the edges are golden, then remove and set aside to cool.
In a large mixing bowl, beat the softened cream cheese with an electric mixer on medium speed until smooth and creamy, about 2-3 minutes.
Add the pumpkin puree, sugar, ground cinnamon, ginger, cloves, nutmeg, and vanilla extract to the cream cheese. Continue mixing until well combined and the mixture is smooth and slightly thickened.
One at a time, beat in the eggs on low speed, just until incorporated. The batter should be smooth and pourable with a slightly fluffy texture.
Pour the filling over the cooled crust, smoothing the top with a rubber spatula for an even surface. Tap the pan gently on the counter to release any air bubbles.
Bake the cheesecake in the preheated oven for 55-60 minutes, or until the edges are set and the center is just slightly jiggly. A toothpick inserted into the center should come out clean or with moist crumbs.
Remove the cheesecake from the oven and let it cool in the pan for about 1 hour. Then, refrigerate for at least 4 hours or overnight to allow it to set completely.
Once chilled, carefully run a knife around the edge of the springform pan to loosen the crust, then gently remove the sides of the pan.
Slice the pumpkin pecan cheesecake with a clean, sharp knife. Serve slices with a dusting of cinnamon or a dollop of whipped cream if desired, revealing the creamy interior and crust with toasted pecans.
