The key to successful gingerbread cookies lies in chilling the dough in the refrigerator overnight. The correct consistency of the dough should be very stiff and even slightly crumbly. When you roll it out (1/4 inch thick), the edges may be split and a little crumbly, so cut from the center, pick up the scraps, put them back in a ball, flatten into a disk and put them back in the fridge to chill before re-rolling and cutting.