In a large sauté pan or braiser, sauté the onion or shallot gently in butter and olive oil until soft and translucent. 

Add in the cubes pork shoulder, raising the heat some, and sauté, seasoning as you go with salt, pepper, nutmeg and rosemary. (Take care to modulate the heat so that the onion doesn't burn.) When the pork is nicely browned, add the white wine and let it evaporate, scraping up the brown bits at the bottom of the pan.

Add the broth or water, perhaps a small glassful, just enough to cover the entire bottom of the pan. Cover and simmer for 30-45 minutes, until almost tender. Check in from time to time to turn the pork and, if need be, add more water or broth to keep things moist. 

When the pork is nearly tender, add the winter squash and continue simmering for another 10 minutes or so, until both the pork and squash are fork tender. Add minced parsley if using and give everything a turn. 

Transfer the pork and squash to a serving dish, together with their cooking juices. If you want a proper sauce, add more water or broth to the pan and, once again, scrape up all the brown bits. Pour over the resulting sauce over pork and pumpkin. Sprinkle with more minced parsley and serve hot.