Cover the dried porcini mushrooms with 1 1/2 C of boiling water and allow to sit for 20 minutes. Strain through a fine mesh strainer and reserve the liquid. Rinse the mushrooms to rid them of any dirt and finely chop.
Place large heavy bottomed pan over medium heat. Add 2 Tbl of olive oil and the pancetta. Cook for 2 minutes until pancetta starts to brown. Add the onion, celery and carrots, cooking for 5 minutes more until the vegetables start to soften. Add the ancho pepper, garlic and porcini mushrooms. Season with a little salt and cook until vegetables are soft. Remove the vegetables and set aside.
Using the same pan, heat the remaining 2 Tbl of olive oil. Add the skirt steak and ground pork. Season with salt and black pepper. Cook over medium high heat until the meat begins to brown, about 15 minutes. Turn the heat down to medium and add the vegetables, wine, bay leaves and thyme. Cook until the liquid evaporates and the mixture begins to brown. Be sure to scrape the brown glaze off of the bottom of the pan. Add 1 cup of the porcini liquid, half of the veal stock and the tomato paste. Cook at a slow simmer, partially covered until liquid begins to thicken. The next few steps take 30 - 40 minutes and are what gives the sauce a rich texture and depth of flavor. Add milk, 2 TBL at a time, stirring the sauce well to incorporate. Continue to cook the sacue gently, adding a few tablespoons of milk when needed. Reduce until the sacue begins to brown again. Add the remaining porcini liquid an dveal stock, stirring and scraping well. The sauce is done when its texture is velvety and the meat is completely tender, about 1 1/2 hours.
To make the gnocchi, combine the garlic, pancetta and butter in the work bowl of a food processor fitted with a steel blade. Process until the mixture becomes creamy in texture. IN a separate bowl, mix the bread crumbs, flour and 1/2 C of the Parmesan cheese. Transfer to a work surface and shape into a mound. Make a hollow in the center of the mound. Put the garlic and pancetta mixture into the hollow and add the nutmeg, eggs and season with salt and black pepper. Draw the sides of the mound together and knead until it is well mixed. Cut into four equal pieces. Lightly flour the work surface. Using your hands, roll the gnocchi dough out into long thin trips about 1/2 inch in diameter. Then, using a paring knife cut into 1 inch pieces. Bring a large pot of salted water to a simmer. Add gnocchi and cook until they return to the surface, about 4 minutes. Strain through a colander and serve with the bolegnese sauce. Sprinkle with the remaining parmesan cheese.