- Preheat the oven to 400ºF and place a 12-cup muffin tin on a rimmed baking pan lined with parchment paper.
- In a bowl, beat together the butter and 1/3 cup of the brown sugar until well combined. Divide this mixture between the 12 cups of the muffin tin and evenly scatter the pecans over top.
- Melt the remaining butter and set aside. In a small bowl, combine the remaining 2/3 cup of brown sugar with the spices and salt and set aside.
- On a lightly floured work surface, unroll one sheet of puff pasty. Brush half of the butter on top then sprinkle on half of the sugar and cinnamon mixture. Roll the pastry up like a jellyroll and slice into six buns. Transfer the buns, spiral side up, to the prepared muffin tin and repeat with the remaining puff pastry and fillings.
- Bake in the preheated oven for 30 minutes or until the buns are a deep golden colour. Remove the buns from the oven and allow them to cool for five minutes. Carefully remove the lined baking pan from underneath the muffin tin, place it parchment side down over the buns, then very carefully invert the whole thing to flip out the buns. Immediately remove the muffin tin and scrape out any remaining caramelized bits and pecans.
- Allow the buns to cool slightly before serving.
*Buns can also be fully assembled, in the pan, a day in advance to be stored in the fridge and baked when ready to serve.