Place potatoes in a saucepan, and cover with water; bring to a boil. Reduce heat, and simmer 1 minute. Drain well.
Heat oil in a small skillet over medium heat; add garlic. Sauté 30 seconds; remove from heat.
Coat hands with cooking spray. Press pizza dough into a 15- x 10-inch jelly-roll pan coated with cooking spray. Coat dough with cooking spray. Bake at 475° for 4 minutes or until set.
Spread sautéed garlic evenly over crust; top with 3/4 cup cheese. Arrange potato slices over cheese, overlapping if necessary. Sprinkle with rosemary, salt, and pepper. Top with remaining 1/2 cup cheese. Bake at 475° for 8 minutes or until cheese melts and crust is golden. Let cool 10 minutes on a wire rack. Cut into 24 squares.