Roll dough out into a large rectangle and transfer to a large baking sheet. Top dough with mozzarella cheese, to within 1/2-inch of the edges and then sprinkle garlic flakes all over cheese. Top with chicken, mushrooms and olives. Sprinkle feta cheese over top and then sprinkle oregano over everything. Bake 10 to 12 minutes, until crust is golden brown and cheese melts.
Serve with Cherry Tomato Salad.
Mixed Cherry Tomato Salad:
In a medium bowl, combine tomatoes and basil. In a small bowl, whisk together vinegar, oil and mustard. Add mixture to tomatoes and toss to combine. Season, to taste, with salt and black pepper.