Philly Cheesesteak Garbage Bread

Name: Philly Cheesesteak Garbage Bread
Ingredients: 5 tablespoons olive oil; 1 pound beef flank steak; Kosher salt and freshly ground black pepper; One 8-ounce container button mushrooms, thinly sliced; 2 medium yellow onions, thinly sliced; 2 medium Cuban or banana peppers, seeded and thinly sliced; All-purpose flour, for dusting; 1 1/2 pounds store-bought pizza dough (see Cook's Note); 2 cups grated American cheese (6 ounces); 2 cups grated provolone (6 ounces); 1 large egg, beaten, for egg wash