Unroll crescent roll dough. Separate into 2 rectangles. Press over bottom and 1/2 inch up sides of ungreased 9x13-inch pan, seal perforations. Sprinkle cheeses over dough.
Combine onion, egg, milk, olives and mushrooms in bowl, mix well. Pour over cheeses. Sprinkle with bacon bits and parsley. Bake at 375° F for 22 to 28 minutes or until brown.
Cool for 5 minutes. Cut into squares.Makes 6