Preheat oven to 425°. Flatten crescent roll dough to cover bottom of a 9 x 13-inch pan. Slice sausages onto dough; sprinkle with Swiss cheese. Combine remaining ingredients. Pour over sausage and cheese. Bake 25 minutes, or until egg mixture is well set. Tastes like a delicious baked omelette with a crust. Add mushrooms if you like. Serves 4 to 6.