Combine flour, baking powder, and salt; stir well. Cut in shortening until mixture resembles coarse meal. Sprinkle 1 1/2 cups milk evenly over flour mixture, stirring until dry ingredients are moistened.
Turn dough out onto a lightly floured surface; knead 10 to l2 times.
Roll dough out to a 1/4-inch thick 15- x 11-inch rectangle; brush with melted butter.
Combine sugar and cinnamon; sprinkle over dough. Roll up jellyroll fashion, beginning at long side; moisten edges with water to seal. Cut roll into twenty-two 1/2-inch slices; place slices, cut side down, on greased baking sheets. Bake at 400° for 15 minutes or until rolls are lightly browned.
Combine powdered sugar and 2 tablespoons milk, beating well. Drizzle over warm rolls.