Place the 2 ½ lb lamb shoulder in a large bowl and drizzle with 3 tbsp distilled white vinegar. Make sure the vinegar coats the outside of the lamb, then fill the bowl with cold water. Pour out the water, then rinse the lamb in more cold water.
In a medium pot, place the lamb meat and fill the rest of the pot with water. Bring the water to a boil, skimming the foam off the top of the water as it is cooking. Boil for 10 minutes.
When the lamb is done being boiled, pour out the water. Rinse the lamb in water again.
Then place the lamb in an instant pot and fill the pot the rest of the way with water (about 12 cups in a 6 quart pot. If you can fit 16 cups in your 8 quart pot, that is even better!).
Place the lid on the pot and cook on HIGH for 30 minutes, ending with an Instant Pressure release. If you are cooking the lamb on the stovetop, cook the lamb in a large pot with 16 cups of water. Cook with the lid on for about 2-3 hours, until it is fall-off-the-bone tender.
When the lamb is done cooking, remove it from the liquid and set the remaining broth aside. Remove the lamb from the bone and set the meat aside.
Pour the reserved broth into a large pot and bring it to a boil. Once boiling, add the 2 onions sliced into rings into the broth and allow them to cook until soft (about 15 minutes). Remove from the broth and set aside.
Salt the broth lightly (remember you will still be eating it, so do not oversalt!). Then add the 18 oz lasagna noodles into the boiling water and cook until soft. Remove from the broth.
Run the pasta under water until it cools. Then cut the lasagna noodles into thirds to make smaller squares. Set aside.
Remove about 2 cups of broth from the pot and set aside the remainder.
Finally, make the chyk sauce. To do so, place the reserved two cups of broth in a smaller pot. Add the third chopped onion, 2 bay leaves, salt, and pepper to taste. Bring this to a boil until the onions are tender, about 5-8 minutes.
Time to serve! To prepare your platter, pile the pasta squares onto a large platter. Then add the cooked onions on top of the pasta, then the lamb meat on top of the onions. Pour your chyk sauce (the 2 cups of broth) over the platter. Sprinkle with parsley, chives, and dill if desired.
Divide the larger portion of brothinto four serving bowls. Sprinkle each serving bowl with fresh dill. The platter goes in the center of the table and each person gets their own bowl of broth!