Preheat the oven to 325℉. Line two baking sheets with sides with parchment paper, or lightly grease the baking sheets. If using a dark-coated baking sheet, lower the oven temperature by 25℉ to prevent over-browning.
In a large bowl, combine the oats, seeds, nuts (if including), shredded coconut, pumpkin pie spice, cinnamon, salt, and brown sugar.
In another bowl, combine the pumpkin, maple syrup, oil, and vanilla.
Pour the wet mixture into the dry mixture, and toss until the oats are thoroughly coated.
Spread the granola onto the prepared baking sheet.
Bake for 20 minutes. Remove the granola and stir. Bake in 10 minute increments or until the granola is mostly dry and crisp. (I typically bake for a total of 40 minutes; see notes.) Remove the granola from the oven and allow to cool.
Mix in the cranberries and any additional nuts or add-ins, and store in an airtight container. Sealed tightly, the granola will stay fresh for several weeks on the counter and for a month or two in the refrigerator.