Grease a 13-inch pizza pan; set aside. Preheat oven to 375 degrees F. On a lightly floured surface, roll bread dough into a 14-inch circle. If dough is difficult to roll out, stop and let it rest for a few minutes. Transfer dough to prepared pan. Build up edges slightly. Prick dough generously with a fork. Bake for 15 to 20 minutes or until light brown.
Meanwhile, in a large skillet cook sausage and mushrooms until meat is brown. Remove from skillet and drain off fat.
In a medium bowl beat together eggs and milk. In the same skillet melt butter over medium heat; pour in egg mixture. Cook, without stirring, until mixture begins to set on the bottom and around edge. Using a large spatula, lift and fold partially cooked eggs so the uncooked portion flows underneath. Continue cooking over medium heat for 2 to 3 minutes or until egg mixture is cooked through but still glossy and moist. Remove from heat.
Sprinkle half of the shredded cheese over the hot crust. Top with scrambled eggs, sausage mixture, and remaining cheese. Bake for 5 to 8 minutes more or until cheese melts. If desired, serve with salsa.