For beef brothels, I strongly recommend the use of an electric slow-cooker (known in these parts as a "crock pot", think what you will).

Take about a kilo of beef shin bones and a large knob of peeled ginger-root and put them in a four-quart crock pot. An onion is nice, even two, but let's not get carried away here. Leave the onion skin on; it helps give brothels a nice golden colour.

Fill the crock pot to about half an inch from the top with water. If you live in place where the tap yields chlorine-tasting if sanitary stuff, use filtered water.

Plug the pot in and turn the heat control to "low". Leave it alone for at least 12 hours; 14 hours is even better. Then discard the hunks of bone, and strain the broth to remove the onion wreckage and the exhausted ginger knob. Then refrigerate the broth to get rid of the substantial quantity of fat that will have been rendered out of the bone marrow.

After that, add what you like: shredded meat, any kind of cookable vegetable, pearl barley, even exotica such as rice and furrin mushrooms. Boil it down to make demi-glace, that stuff chefs crave. Drop an egg white in it to clarify it, and you get bouillon; put sherry in it and you get what my grandmother used to have at her club on Thursdays.