"Pitcha is a calf's foot jelly historically served during Jewish holidays. It's a cold gelled appetizer made of cooked calf's foot, garlic, onion, bay leaf, clove, peppercorns, lemon juice, and hard boiled eggs. If you can't find calf's foot, you can substitute oxtails."
Ask your butcher to chop the calf's foot in several pieces; wash well. (If you're using oxtails, leave the pieces whole and do not remove fat or bones until later.) Place the meat in a stock pot with the bouillon cube. Tie the chopped onion, garlic, bay leaf, clove, and peppercorns into a cheesecloth bag. Add the bag to the pot and pour in water to cover. Bring the water to a boil over high heat. Reduce the heat and simmer for 3 hours.
Stir the gelatin into the 1/2 cup of cold water and set aside for 10 minutes. Remove the meat from the pot and let it cool. Strain the cooking liquid into a bowl; you should have about 8 cups of broth. Discard the spice bag. Pick the meat from the bones and set it aside; discard the bones and gristle.
Spray a gelatin mold with cooking spray. Add the lemon juice and salt and pepper to the broth. Taste and adjust the seasonings. Transfer the softened gelatin into the warm broth and stir to dissolve. Pour the liquid into the prepared mold and refrigerate. Chill the broth until the gelatin has thickened slightly, about 45 minutes to 1 hour. Stir in the reserved meat and the egg slices. Refrigerate until set, 4 hours or overnight.
To unmold the pitcha, dip the gelatin mold into warm water for 15 to 20 seconds. Invert the mold onto a serving plate and serve with parsley and lemon wedges.