Rinse the beef feet and tripe thoroughly under cold water. Place them in a large pot and cover with water. Bring to a boil and let it boil for about 10 minutes. Drain the water and rinse the meat again to remove any impurities.
Refill the pot with fresh water and add the cleaned beef feet and tripe. Add the chopped onion, minced garlic, bay leaves, and black peppercorns. Bring to a boil, then reduce the heat to low and let it simmer for 6-8 hours, or until the meat is tender and gelatinous.
During the cooking process, skim off any foam or impurities that rise to the surface.
Once the meat is cooked, season the broth with salt to taste. Remove the bay leaves and discard.
Ladle the khash into bowls, making sure each bowl gets a generous portion of meat and broth.
Garnish with freshly chopped parsley. Serve hot with lemon wedges, flatbread or lavash, and vinegar and garlic sauce on the side for added flavor.
Enjoy your meal!