Pulse 1½ cups flour, sugar, and salt in food processor until combined, 2 pulses. Add cubed butter and process until homogeneous paste forms, 40 to 50 seconds.
Using your hands, carefully break paste into 2-inch chunks and redistribute evenly around processor blade. Add remaining 1 cup flour and pulse until mixture is broken into pieces no larger than 1 inch (most pieces will be much smaller), 4 to 5 pulses.
Transfer mixture to medium bowl. Add grated butter and toss until butter pieces are separated and coated with flour.
Sprinkle ¼ cup ice water over mixture. Toss with rubber spatula until mixture is evenly moistened. Sprinkle remaining ¼ cup ice water over mixture and toss to combine. Press dough with spatula until dough sticks together.
Use spatula to divide dough into 2 portions. Transfer each portion to sheet of plastic wrap. Working with 1 portion at a time, draw edges of plastic over dough and press firmly on sides and top to form compact, fissure-free mass. Wrap in plastic and form into 5-inch disk. Repeat with remaining portion; refrigerate dough for at least 2 hours or up to 2 days.