Directions

• In a 5 quart pressure cooker, add 3 cups of water. Add the beef shanks and season with some salt as you layer them in the pot. Add the bone marrow,  1/2(whole piece) of the onion, head of garlic, bay leaves, peppercorns and 1/3 of celery. Reserve the remaining onion, garlic and celery for later in the recipe. Add just enough more water so it comes 1/2 an inch below maximum fill line. Secure and the lid and lock. Turn heat to high.
• Once the safety valve locks and the pressure release valve begins to hiss and rotate, turn heat to low. On an electric stove that would be number 2. Set timer for 1 hour. The pressure cooker will yield a much more concentrated broth and the most tender meat.
• After 40 minutes, add 8 cups of water to a large soup pot. Season with 1 teaspoon of salt and bring to a boil. Reduce to a simmer. Add the carrots, chayote, celery, diced onion, minced garlic and tomatoes. Cook for 10 minutes.
• By this time the beef should be just about done. If timer has gone off, remove pressure cooker from heat and let sit until safety valve unlocks.  Once it unlocks, carefully remove the lid. Remove all the beef(discarding excess fat) and transfer to simmering soup.  Strain the solids from the beef stock and discard the solids. Skim the fat on the top of stock. Add remaining beef stock to soup pot.
• To the simmering soup, add in the potatoes. Time it for ten  more minutes, add the corn,  again wait 10 minutes, then the squash.  Finally the cabbage and cilantro at the end. Cook for ten more minutes or until cabbage is cooked through. Remove from heat.  Ladle soup into serving bowls and garnish with serrano salsa, lemon(or lime) and fresh cilantro if desired. Serve with warm corn tortillas and rice.  We like to spread the bone marrow on the warm tortilla with serrano salsa, lemon and salt. Yields 6-8 servings.