How to make
Clean the beef kidneys from skins and fat. Cut them into pieces and leave them in water to soak.
Melt the butter in a deep pan. Add the strained kidney pieces and stew them, until they have browned well. Remove them with a slotted spoon.
Put the washed mushrooms in the pan and stew them. When they aquire a golden brown color, add the cream, the crushed broth cube and stir vigorously, until the cream has dissolved.
Add the mustard and return the kidneys back into the pan. Season with salt and black pepper.
Serve the dish warm.
The beef kidneys with cream and mustard are ready.