Rinse the beef and marrow bone under cold water to remove any loose fragments. Peel and trim the vegetables, keeping them in large pieces so they hold their shape during the long simmer. Leave the onion skin on, as it gives the broth its warm golden colour. Set everything aside before starting the broth.

Place the beef and marrow bone into a large stockpot and pour over the cold water. Bring the pot slowly to a gentle simmer over medium heat. As foam rises to the surface, carefully skim it away with a spoon to keep the broth clear and refined. Continue skimming before moving to the next stage.

Once the broth is mostly clear, add the carrots, parsley roots, celery root, onion, garlic, kohlrabi, tomato, green pepper, salt, and peppercorns. Reduce the heat immediately so the soup barely trembles rather than boils vigorously. A slow simmer preserves both clarity and delicate flavour.

Allow the soup to cook uncovered for 2½ to 3 hours. Resist stirring the broth, as too much movement can cloud it. Check occasionally and skim away any excess fat or foam from the surface while the flavours deepen naturally.

After several hours, the beef should feel tender when pierced with a fork, and the vegetables should be soft but not collapsing. Taste the broth and adjust the salt carefully if needed. Traditional Húsleves should taste rich yet balanced rather than heavily seasoned.

Remove the meat and vegetables carefully with a slotted spoon. Strain the broth through a fine sieve into a clean pot to achieve a beautifully clear soup. Discard the peppercorns and onion skin before continuing.

Bring a smaller pan of salted water to the boil and cook the soup noodles according to the packet instructions. Cooking them separately prevents the broth from becoming starchy or cloudy. Drain the noodles and keep warm for serving.

Cut the cooked carrots into smaller pieces and shred or slice the beef neatly. Some Hungarian households serve the meat separately with mustard or horseradish, while others return part of it directly to the soup. Arrange everything before plating.

Place a small portion of noodles into each bowl, ladle over the hot broth, and add carrots and beef. Finish with finely chopped parsley for freshness. Serve piping hot with crusty bread and a little extra horseradish on the side for a traditional Hungarian touch.