Melt butter in medium saucepan over medium heat. Add prosciutto, onion, bay leaf, pepper flakes, and 1/4 teaspoon salt and cook, uncovered, stirring often, until onion is soft and beginning to turn golden, about 8 to 12 minutes. Add garlic and cook until aromatic, about 1 minute. Increase heat to medium-high, add tomato paste and sun-dried tomatoes and cook, stirring constantly, until slightly darkened, about 2 to 3 minutes. Add 1/4 cup wine and cook, stirring often, until liquid has evaporated, about 2 minutes. Add 2 cups crushed tomatoes and bring to the boil. Reduce heat to low and simmer, partially covered, stirring often, until sauce reduces and is thickened, about 25 to 30 minutes.

While sauce simmers, bring 4 quarts water to the boil in a large pot, add 1 tablespoon salt, and drop in pasta all at once, and cook according to package directions or until al dente. Drain pasta in a colander, reserving 1/2 cup cooking water, and transfer back to cooking pot.

When sauce has thickened, remove and discard bay leaf. Stir in cream, remaining 1/4 cup crushed tomatoes, and remaining 2 tablespoons wine, and cook until warmed through, about 1 minute. Adjust seasoning with salt and pepper to taste. Add sauce to cooked pasta and toss to combine, adjusting consistency with reserved pasta cooking water as necessary. Stir in basil. Serve immediately, passing freshly grated cheese separately.