Rinse the beef and place it in a large pot with the chopped vegetables, allspice grains, and bay leaves. Pour in 1 ½ liters of water until the meat is covered. Bring to a boil over high heat, then reduce heat to medium-low. Cover and simmer for 90 minutes.
Remove the meat from the broth and let it cool for about 10 minutes. Cut it into small cubes. Strain the broth through a sieve to remove the vegetables. Allow the broth to cool completely (ideally overnight), then skim off the fat.
In a saucepan, melt butter over medium heat, then add flour. Cook, stirring constantly, for 2–3 minutes. Gradually pour in the strained broth and milk while stirring constantly to prevent lumps. Stir in crème fraîche and chopped dill. Season to taste with salt, pepper, and nutmeg.