Once slightly cooled and able to be handled, place the roasted pecans in a high quality blender. I have a Ninja and it worked perfectly.
Blend the nuts until smooth. This took me about 5 minutes or so, scraping the sides down with a spatula. Once smooth, add in the brown sugar and pumpkin pie spice. Blend again until smooth and combined.
Store in a glass jar. I don't recommend storing at room temperature, but it will keep for up to a month or more in the refrigerator.
As with any nut butters, each use you might need to stir the oils back in. It's normal. Enjoy!