Melt 1 tablespoon of the butter in a large sauté pan or Dutch oven over medium-high heat. Add the pancetta and cook, stirring frequently, until it is crisp and has rendered most of its fat, 3 to 4 minutes. Lower the heat to medium and add the shallots; cook, stirring until softened, 1 to 2 minutes.
Add the remaining 2 tablespoons of butter and when it has melted, add the tomatoes, salt, pepper and oregano, and cook, stirring, until the sauce has thickened and flavors have come together, about 10-12. Add 1/4 cup Parmesan to the sauce, stir, remove from the heat and cover with a lid to keep warm.
Divide the cooked pasta among 4 serving plates.
Spoon some of the sauce over the top of the pasta and garnish with the remaining Parmesan and with freshly ground black pepper.
Yield: 4 servings