Place the marrow bones on the bottom of the pan (later the meat should lie on the bones and not touch the bottom of the pan, and the water will circulate evenly around the meat), on top of the ribs.
Pour 4 liters of water and bring to a boil. Remove the foam and cook on very low heat for 5 hours (the water should not boil, but only slightly "move"). While cooking the soup, periodically add a couple of spoons of ice water or a couple of pieces of ice, the soup will be more transparent and delicious.
Prepare the vegetables.
Vegetables cut into thick circles.
"fry" for 2-3 minutes on a dry pan.
Half of the onion to fry until brownish color on the cut.
Put meat, salt, pepper, vegetables, onion, parsley, bay leaf, tomatoes in the broth (liver, mushrooms, cabbage, spleen - optional), add water, bring to a boil for a few minutes, cook for 3.5 - 4 hours on low heat.
Parsley, leek stalk, bay leaf - remove. Let the soup brew for several hours, preferably overnight.