Line 2 large baking sheets with parchment. Divide dough in half. Roll out 1 half on lightly floured surface to 13 1/2″ x 8 1/2″ rectangle. Transfer to a baking sheet. Repeat with second half.
Spread 1/4 cup marinara sauce over each pizza, leaving 1/2-inch border. Sprinkle cheeses over, then mushrooms and pancetta. Sprinkle with salt and generous amount of pepper.
Bake pizzas until brown on bottom and cheese is melted, about 15 minutes. Cut each pizza crosswise into rectangles.
Notes
Allow the pizza to stand five minutes before slicing to allow any liquid on top time to be reabsorbed into the toppings so the crust won’t get soggy.