Position racks in the upper and lower thirds of the oven and preheat to 425 degrees . Crumble the biscuit dough into a greased 9- to 10-inch cast-iron skillet and press evenly to fill the bottom of the pan. Brush with the beaten egg white and sprinkle with 1/2 tablespoon sugar; scatter the pineapple evenly on top, leaving a 1/2-inch border.
Bake the pizza on the lower rack until golden-brown around the edge, about 17 minutes. Remove the pan from the oven and preheat the broiler. Sprinkle the remaining 1 tablespoon sugar over the pineapple and broil until golden-brown in spots, about 5 minutes. Slice and serve warm with the ice cream.