Press crescent rolls into bottom of greased 9 x 13 baking pan. Layer crescent rolls with summer sausage. Sprinkle with 4 T. of the parmesan cheese. In separate bowl, beat the eggs with the milk. Add the mushrooms, salt and pepper. Pour the egg mixture over the top. Sprinkle with remaining parmesan cheese. Bake at 350° for 35 minutes.