Step 1

In a large enameled cast-iron casserole, cook the bacon in the oil over moderate heat, stirring occasionally, until the bacon is crisp, about 5 minutes. Add the carrot, celery, onion, garlic and a generous pinch of salt and cook over moderate heat, stirring occasionally, until just starting to brown, about 5 minutes. Add the ground veal, sage, parsley, bay leaf, oregano and basil and cook, breaking up the meat with a wooden spoon, until no pink remains, about 8 minutes.

Step 2

Add the wine to the casserole and cook, stirring, until nearly evaporated, about 3 minutes. Add the tomatoes with their juices and cook, stirring, until the liquid has reduced by half, about 4 minutes. Add the stock and bring to a simmer. Cook over moderately low heat, stirring occasionally, until slightly reduced, about 8 minutes. Stir in the squash and simmer, stirring occasionally, until the squash is tender, about 25 minutes. Discard the sage, parsley and bay leaf. Stir in the heavy cream and season the sauce with salt and white pepper; keep warm over very low heat.

Step 3

In a large pot of salted boiling water, cook the pasta until al dente. Drain well and transfer the pasta to deep bowls. Spoon the sauce over the pasta, garnish with thyme and serve.