Mix 12 tablespoons of unsalted butter and ⅓ cup of light brown sugar together.
Place 1 tablespoon of the butter and sugar mixture in the bottom of each muffin cup.
Top each cup with pecans.
Unfold the puff pastry on a lightly floured surface.
Brush the puff pastry with melted butter, leaving a 1 ½ inch border.
Sprinkle ⅓ cup of brown sugar and 1 ½ teaspoons of cinnamon evenly over the puff pastry, again leaving a 1 ½ inch border.
Sprinkle ½ cup of raisins over the sugar and cinnamon.
Tightly roll up the puff pastry, starting from the short side.
Cut the roll in half, then cut each half into thirds to make 6 buns.
Place the buns, cut side down, in the muffin cups.
Bake at 400°F for 30 minutes until the pastry is firm and the butter, sugar, and pecans are caramelized.
Invert the buns onto a plate to serve.
