Carefully scoop out the insides of a large onion.
Heat some olive oil in a pan over medium heat and brown the beef chunks. Add the scooped out onion pieces to the pan, along with the carrot and celery root, and sauté for about 5 minutes. Deglaze the pan with the red wine, let the sauce reduce, and then stir in the beef broth. Season with salt and pepper, let simmer in the pan for about 45 minutes, and then spoon the beef goulash into the hollowed-out onion.
Grate the raw potatoes, rice the boiled potatoes, and combine the two mixtures. Add the egg yolks, corn starch, and salt and mix until smooth. Place a piece of parchment paper on your work surface, spread the potato dumpling dough over it, top with another piece of parchment paper, and roll the potato dumpling dough out into a sheet that's about ⅓-inch thick. Remove the top piece of parchment paper, place the stuffed onion in the middle of the potato dumpling dough sheet, and use the bottom piece of parchment paper to form the dough around the stuffed onion.
Fill a pot with 1-2 cups of water over medium heat and bring to a boil. Place a glass bowl upside-down in the center of the pot, place the stuffed potato dumpling on top, cover the pot with a lid, and let steam for 35-40 minutes.
Serve the beef goulash potato dumpling on red cabbage and garnish with buttered bread crumbs, cranberry sauce, and parsley.