For the Cinnamon Swirl:

1. In a small bowl, combine the brown sugar, cinnamon, and nutmeg.
2. Cut the butter into small pieces and add to the mixture. Using your fingers, cut the butter into the spiced sugar until it is evenly combined. Place in the fridge until ready to use.

For the Pumpkin Bread:

1. Preheat the oven to 350 degrees F (180 degrees C). Line a 9x5 loaf pan with parchment paper.
2. In a large bowl, whisk together the flour, baking powder, pumpkin pie spice, and salt. Set aside.
3. In a medium bowl, whisk together the pumpkin puree, brown sugar, granulated sugar, oil, eggs, and vanilla. 
4. Fold the wet ingredients into the dry ingredients until fully combined. Be sure to get out all of the pockets of dry ingredients at the bottom of the bowl. 
5. Pour half of the batter into the loaf pan, then sprinkle the cinnamon swirl mixture evenly on top. Pour the rest of the batter into the loaf pan and smooth out the top as well as you can. 
6. Generously sprinkle turbinado sugar on top of the batter. 
7. Bake the pumpkin bread for about 65 minutes or until a toothpick inserted comes out clean. 
8. Allow to cool a few minutes in the pan before removing. Cool completely before slicing.