How to Make It
In a large skillet, heat the olive oil until shimmering. Add the veal and sausage and season with salt and pepper. Cook over moderately high heat, stirring occasionally and breaking the meat into walnut-size pieces, until just browned, about 20 minutes. Add the fennel, carrot and garlic and cook until the vegetables begin to soften, about 4 minutes.
Add the milk and simmer until reduced by three-quarters, about 5 minutes. Add the wine, tomatoes, tomato paste and marjoram and cook until reduced by half. Add the stock, season with salt and pepper and simmer over low heat until the liquid has reduced by three-quarters, about 20 minutes.
In a large pot of boiling salted water, cook the penne until al dente; drain. Add the penne to the veal sauce and cook over moderate heat, stirring to coat the penne with the sauce. Divide the penne among 6 bowls, sprinkle with the reserved fennel fronds and serve, passing the cheese at the table.