Do-ahead steps: Defrost the puff pastry overnight in the refrigerator and leave in the refrigerator until ready to roll out. If you leave it on the counter while you assemble everything they get too soft and will be difficult to work with. Preheat oven to 400°.
With a hand mixer or stand mixer cream together and place one rounded tablespoon of mixture in to each muffin cup. Sprinkle ½ cup of the chopped pecans evenly over the sugar butter mix: 7 TBS of butter, 1/3 cup brown sugar and ½ t vanilla extract
With a fork combine remaining brown sugar and the spices. Divide mixture in half: one half for one puff pastry sheet, and one for the second: 2/3 c brown sugar, 3 t cinnamon, ½ t nutmeg, ¼ t salt.
Tear off a sheet of plastic wrap larger than the puff pastry sheet and place on a wooden board. Lightly flour the area and unfold one sheet of the defrosted puff pastry with the folds going left to right. With a pastry brush, paint the sheet with melted butter, reserving ½ for the second sheet. Sprinkle brown sugar/spice mixture over the puff pastry and then top with ½ cup of chopped pecans. Starting with the end closest to you, roll snugly, just like a jelly roll ending with seam side down. Slice in to six equal pieces. Each piece is about 1 ½ inches wide. Place each piece spiral side up in the muffin cups. Repeat with the second sheet of puff pastry to make 12 Chelsea Christmas Buns.
Bake at 400° for 30 minutes. Cool for just five minutes before turning out on to a foil or parchment paper lined sheet pan.
Optional spice ideas: cardamom, ginger, allspice.
Optional dried fruit ideas: cranberries, cherries, raisins, golden raisins, apricots, currants, dates.