Preheat oven to 275 Fahrenheit (135 Celsius). Line large 13x18 inch (33cm x 45cm) sheet pan with parchment paper (do not use a silpat).
Rough chop half the pecans. Then, transfer all the pecans to a large mixing bowl. To the pecans, add the other dry ingredients: oats, sunflower seeds, pepitas, pecans, brown sugar and spices. Mix. Set aside.
In a small sauce pot, getnly warm the pumpkin, coconut oil, maple syrup and vanilla extract just warm to the touch. Whisk well to incorporate the ingredients.
Pour the wet ingredients into the dry ingredients. Using a wooden spoon, mix well, incorporating all the ingredients so that every little oat grain is coated with delicious pumpkin spice mix.
Transfer the mixture to the prepared sheet pan, pushing the granola into the corners. Spread evenly, then using the back of wooden spoon, firmly press the granola into the pan.
Bake at 275 Fahrenheit (135 Celsius) for 60 minutes. Do not stir. Rotate the pan, and increase the temperature to 300 Fahrenheit (150 Celsius) for 10-20 minutes. The granola will be fragrant and toasty golden brown yet still somewhat soft to the touch. It will firm up as it cools. Don't be tempted to stir if clustering is desired.
Remove from oven and allow the granola to cool completely in the pan (if you can), about one hour, before gently tossing with cranberries. Handle the granola gently to retain chunky clusters.
Store in a covered container for about a week.