Set your oven to 325°F and line a large rimmed baking sheet with parchment paper or a silicone mat. This lower temperature is key for pumpkin granola because the puree has more moisture than a typical granola recipe, so it needs a gentler bake to crisp up properly without scorching on the edges.
In a large bowl, combine the rolled oats, pepitas, chopped pecans, pumpkin pie spice, and salt. Give everything a good stir so the spices distribute evenly throughout the oats instead of clumping in one spot. This step only takes a minute but it makes sure every bite gets that warm, spiced flavor.
In a small saucepan over medium-low heat, whisk together the pumpkin puree, maple syrup, melted coconut oil, and vanilla extract. Heat just until everything is smooth and slightly warm, about 2-3 minutes. You're not trying to cook it, just loosen the pumpkin puree so it coats the oats easily.
Pour the warm pumpkin mixture over the dry ingredients and stir with a rubber spatula until every oat and seed is coated. The mixture will look thick and sticky, which is exactly what you want since it's what creates those chunky granola clusters everyone loves.
Transfer the mixture to your prepared baking sheet and press it into an even layer using the back of your spatula. Bake for 25-30 minutes, stirring gently halfway through so it browns evenly on all sides. Watch it closely in the last 5 minutes since pumpkin granola can go from golden to burnt quickly.
Once baked, let the granola cool on the pan without touching it for at least 20 minutes. This resting time is what allows the clusters to firm up and harden. If you add cranberries or raisins, fold them in once the granola has fully cooled so they stay soft and chewy.