Pro Tip: Snap butter with your fingertips to break it up and mix into flour to get the best consistency for biscuit dough. A food processor will work if you are in a hurry, but it is best to use your fingers. The small pieces of butter aerate the dough to make the biscuits rise. Before snapping, make sure your hands are cold. If necessary, dunk warm hands in ice water and dry them before immersing into the butter and flour mixture.
Try to incorporate butter into the dry ingredients as fast as possible, and start turning the mixture over with both hands in a snapping motion using all of your fingertips and thumbs. If you hands warm up, dunk them in ice water again. Snap until your pieces of butter are about pea-size, and butter is equally covered in flour. Be careful not to overdo it. It's better to have some larger pieces than overworked butter.