Peel and coarsely chop the onion and carrots and fry them in some beef dripping (or the fat that has exuded from the bones) until nicely browned.
Put all the browned bones and vegetables in a large pan with
After the first skimming, throw in a handful of ice cubes or pour in 300ml / ½pt of cold water, bring back to the boil and skim again. Repeat this 3 times.
Add the remaining ingredients, lower the heat and simmer uncovered for at least 8 hours, and for as long as 12. It must not boil, or the glue element will be extracted from the bones, which will cloud the stock and give it an unacceptably bony flavour.
Obviously there will be evaporation, so add more water from time to time. However, experience shows that after skimming and once you have achieved the barest simmer (steam coming off the surface, but no bubbles rising) this amount of stock can be left to cook overnight without drying out and burning. (Before doing so, however, it is a good idea to make the stock for the first time during the day, then you can work out whether your hob will allow you to leave a pot simmering all night without your sitting bolt upright in the early hours wondering whether you can smell something burning.)
Strain the stock into another saucepan and leave to cool. Refrigerate once cool. The stock will then gel and any remaining fat will solidify on the surface - this can then be removed before use.
The stock will keep indefinitely if boiled up twice a week. It also freezes well: try reducing it down by about half and then freezing it in ice-cube trays; the cubes can then conveniently be used 1 or 2 at a time.