In a large, heavy skillet, heat the EVOO, 2 turns of the pan, over high heat until smoking. Stir in the veal to brown slightly, then stir in the pork (or sausage), crumbling the meat. Add the carrot, celery, onion, garlic and sage; season generously with salt and pepper. Cover and cook the vegetables, stirring occasionally, until softened, 3 to 5 minutes. Stir in the tomato paste, then stir in the wine to deglaze, scraping up the browned bits from the bottom of the pan.
Stir the vegetable stock and porcinis into the ragu. Stir in the milk, lower the heat to medium-high and cook, stirring occasionally, until thickened, about 45 minutes.
Bring a large pot of water to a boil, salt it, add the pasta and cook until al dente. Drain, reserving 1 cup of the pasta cooking water.
Stir the reserved cooking water into the ragu. Add the pasta and toss. Top with the pecorino-romano.