Differs from a pizza in..... The Crust: It uses an incredibly thin, rolled-out unleavened dough made without yeast, giving it a light, cracker-like crunch. The Base: Instead of a tomato-based pizza sauce, the dough is heavily spread with crème fraîche or schmand (a thick soured cream) seasoned with nutmeg, salt, and pepper.Traditional Toppings: The classic version is topped simply with smoky bacon cubes (speck) and thinly sliced onions.