Thaw the pork legs, soak in cold water for 2 hours, then scrape, rinse and chop into pieces. Open a can of peas. Peel and wash the vegetables. Wash the dill and chop coarsely. Pass the garlic through a press. Prepare forms for jellied meat.
Boil meat and vegetables for jellied meat. Place the legs in a saucepan, add water (5 cm above the meat), place over high heat and bring to a boil. Then reduce the heat, cover and simmer for 3 hours. Then add the whole onions and carrots and cook for another 1.5 hours. Then add garlic, peppercorns, bay leaf, dill, salt and cook for another 30 minutes. Remove the meat and carrots and let them cool.
Prepare jellied meat. Remove skin, bones and excess fat from the meat and chop finely. Chop the carrots. Strain the broth through a sieve. Place finely chopped pork legs, carrots, peas in a jellied dish, pour in broth, cover with a lid and refrigerate for 8 hours.
Serve jellied pork legs with mustard.