Pasta all'Amatriciana Recipe

Ingredients

• 3 pounds guanciale, sliced 1/4-inch thick
• 2 large Spanish onions, roughly chopped
• 6 shallots, thinly sliced
• 2 cups dry white wine
• 2 tablespoons crushed red pepper flakes
• 4 quarts store-bought marinara sauce
• 1/2 cup water, if needed
• freshly ground black pepper, to taste
• 2 pounds cooked paccheri pasta