You can serve this soup with a ramekin of potato alongside the soup bowl, have everyone scoop their crunchy potatoes into their soup bowl when the dish is passed around, or place the potato mixture from each individual tin directly into each soup bowl.
Whichever way you choose to serve this dish, there is one common factor: This is the perfect outdoor Succos food to chase away the evening chill.
Heat oil in an eight-quart pot. Add onion and sauté for five to seven minutes.
Raise heat and add the flanken pieces. Season lightly with salt and pepper. Allow meat to brown about five minutes. Stir mixture and turn meat over. Season lightly with salt and pepper and brown the second side for five minutes.
Add in the green cabbage and marrow bones, then pour in water until mixture is covered.
Add in the tomato sauce, tomato paste, and sugar. Season with salt and pepper. Allow mixture to reach a rolling boil. Lower flame and allow soup to simmer for two to three hours.
The longer you allow the soup to simmer, the more the flavor intensifies.
The meat and marrow bones give off a lot of fat. This soup is fabulous when prepared in advance. Whether you refrigerate or freeze, before reheating skim off the fat from the top.
Peel and quarter the potatoes. Place the potatoes in a large pot and cover with water and a dash of salt. Boil 20 minutes or until fork tender.
While potatoes are boiling, dice the onion and sauté in one tablespoon oil for 15 minutes. Raise flame and slightly brown the onions.
Drain potatoes well. Mash until smooth. Add in the margarine and spices. Add in the sautéed onion. Mix well. Add in the egg yolk and mix very well.
Divide the potato mixture evenly between either 10–12 ramekins, greased muffin tins, a 9- x 13-inch (23- x 33-centimeter) pan, or oven-to-tableware. (The potato mixture can be frozen at this point.)
Preheat oven to 350°F (180°C) and bake. For the 9- x 13-inch (23- x 33-centimeter) pan, bake about one hour or until the top is browned. For ramekins or filled muffin tins, bake 35 minutes. The result is a crispy, crunchy brown top with a soft center.
If you bake the mixture after freezing, your baking time will be longer, up to an hour and a half for a 9- x 13-inch (23- x 33-centimeter) pan and up to one hour for muffin tins or ramekins.