Using a large, Dutch oven or a heavy-bottomed pan, preheat 2 tablespoons butter and two turns of the pan’s worth of olive oil over medium heat.

Sauté the pancetta until crispy (about three minutes). Add the onion, carrot, and celery and sauté an additional eight minutes or so. Remove from the pan, reserving the cooking oil.

Use a little more oil if necessary, and add the meat to the pan. Season generously with salt and pepper and a good-sized pinch of ground nutmeg. Break up the meat into smaller pieces using a wooden spoon. Brown on all sides.

Return the vegetables and pancetta to the pan and add the wine. Simmer until the sauce almost completely evaporates. (About a quarter of the liquid should be left in the pan.) Add the stock and reduce it by half. Add the tomatoes, sage, and bay leaf. Reduce heat to low. Cover the pan, and simmer for an hour and a half, stirring occasionally.

Check the sauce roughly 20 minutes prior to serving. If it seems thin, remove the cover and simmer until thick and fragrant. Taste and adjust seasoning. Remove the sage and bay leaf and discard.

Bring a large pot of water to a boil. Season generously with salt. Cook pasta per package instructions, less than a minute or two. Remove the pasta from the sauce and allow it to finish cooking there to absorb more flavor. Toss the pasta and the sauce together with the Parmesan and Pecorino Romano until the cheese is melted. Serve immediately.