Heat oven to 350F.
Spray cookie sheet with cooking spray.
In small bowl, mix sugar and cinnamon until well blended. Set aside.
Unroll dough on work surface; press to form 12x8-inch rectangle.
Brush with half of the melted butter; sprinkle evenly with 4 teaspoons cinnamon-sugar mixture. Starting at one short end, fold dough in half.
With pizza cutter or sharp knife, cut into 8 (1-inch) strips.
Twist each dough strip and circle dough around two fingers to create space to tuck one end through to form a knot. Then, tuck ends under and place on cookie sheet.
Brush buns with remaining butter; sprinkle evenly with remaining cinnamon-sugar mixture.
Bake 14 to 16 minutes or until golden brown.
Remove from cookie sheet to cooling rack. Cool 5 minutes. Serve warm.