Place flour, sugar, and salt in a large mixing bowl and mix well. Using the largest holes on a cheese grater, grate frozen butter into flour and toss gently to combine. Pour in ice water and using a spatula, gently stir to bring together dough. Use your hands to gently knead and bring the dough together into a disk. Add a little more water if the mixture is too dry. The key is to add just enough water to make the dough come together into a cohesive disk. You want to handle the dough as little as possible as the more you handle the dough, the tougher it gets. Wrap the disk in plastic wrap and let rest in refrigerator for 1-2 hours.