Cornmeal, for dusting
For the topping:
8 ounces pancetta, cut into 1/2-inch to 1/4-inch pieces
2 large or 4 small shallots, peeled, cut into 1/4-inch pieces
2 small bunch broccoli rabe (rapini), trimmed and cut into 1-inch pieces, stems included
4 cloves garlic, peeled, halved and grated, any green centers discarded
1 teaspoon salt
2 teaspoon Aleppo pepper (see Recipe Notes) or crushed red pepper flakes
1/3 cup good-quality jarred or homemade marinara sauce
10 to 12 ounces thinly sliced scamorza or mozzarella cheese
Make the dough: In the bowl of a food processor fitted with a metal blade, combine the water, yeast, and sugar and process for 2 (1-second) pulses. Let stand for 3 to 4 minutes, until foamy.
Add the flours, salt, buttermilk, and oil and process in 10 to 20 (1-second) pulses, until the dough forms a soft ball. Process for another 20 seconds; stop the machine and feel the dough with your hands. It should be soft and a little tacky at this point. If it is too dry, add another tablespoon of water and process another 40 to 60 seconds, until you have a soft, smooth, but slightly tacky ball. Place the dough into a large bowl and cover with plastic wrap. Refrigerate for at least 8 hours or up to 2 days.
Just before baking, remove the dough from the fridge and let it come to room temperature. Line a platter with paper towels and position it near the stovetop.
Divide the dough in half, and shape each half into a ball. Cover both lightly with plastic wrap and let rest for 25 to 30 minutes to allow the gluten to relax.
While the dough is resting, make the topping: Heat a large sauté pan over high heat, add the pancetta, and cook, stirring, for 4 to 5 minutes, until the pancetta is fully browned and the fat has been rendered. Using a slotted spoon, remove the pancetta to the prepared platter to drain. Reserve the pan and its contents.
Heat the pancetta pan over medium heat until the rendered fat shimmers. Add the shallots and cook, stirring occasionally, for 2 to 3 minutes, until translucent. Add the broccoli rabe and cook, stirring occa