Sauerkraut with Mushrooms

Rinse the dried mushrooms and soak them in warm water for 15 minutes until softened, then drain and chop into bite-sized pieces, reserving the soaking liquid.

Blanch the beef bones in boiling salted water for 5 minutes to remove impurities, then drain and rinse thoroughly under cold water.

Peel and chop the carrot and onion into uniform pieces about 1 cm in size.

Heat the fat in a heavy-bottomed pot or Dutch oven over medium-high heat, then add the chopped carrot and onion, cooking for 3-4 minutes until softened and lightly golden.

Sprinkle the flour over the vegetables and stir continuously for 1-2 minutes until the flour is incorporated and lightly browned.

Add the tomato paste to the pot and stir well to combine with the flour and vegetables, cooking for 1 minute to develop the flavor.

Place the blanched beef bones into the pot, then add the sauerkraut, chopped mushrooms, the reserved mushroom soaking liquid, bay leaf, and season with salt and pepper to taste.

Bring the mixture to a boil, then reduce heat to low, cover partially, and simmer gently for 60-70 minutes until the beef bones have released their flavor and the sauerkraut is tender.

Remove the pot from heat and stir in the sour cream until fully incorporated, adjusting the seasoning with salt and pepper as needed.

Finely chop the fresh greens and scatter them over the stew just before serving, allowing the residual heat to slightly wilt them.