1. On a lightly floured surface, roll dough into a 6″ x 13″ rectangle about ½” thick. Spread butter over dough, leaving a ½” border.
2. Working from one narrow end, fold dough in thirds crosswise, as you would a letter.
3. Rotate dough 90°; roll dough into a 6″ x 13″ rectangle and fold in thirds again. Rotate, roll, and fold dough twice more. Cover with plastic wrap; chill overnight.
4. Next day, cut dough into 2″ squares; place cut side up in an ungreased muffin tin. Cover with plastic wrap; before baking, set in a warm place until doubled in size.