Unroll 1 package of crescent rolls into a 13 x 9-inch baking dish. Press together perforated edges.
Mix together sugar, cinnamon and flour. Toss in apples. Spread on top of crescent rolls in baking dish.
On lightly floured surface, unroll second package of crescent rolls. Press together perforated edges. Carefully place crescent roll dough on top of apples, seal edges. Cut 3 slits in top of crust.
Bake for 30 to 40 minutes or until crust is golden brown. Remove from oven and cool slightly on a wire rack.
Mix together powdered sugar, softened butter and milk until of drizzle consistency, adding more or less milk if needed. Drizzle over warm apple bars, serve.
