Roast beef or veal bones until deeply browned
Add tomato paste and roast briefly
Transfer bones to a stockpot
Add mirepoix: onions, carrots, celery
Add garlic and bouquet garni if desired
Cover with cold water
Bring to a gentle simmer
Skim impurities from the surface
Simmer slowly for several hours
Strain the stock
Make a brown sauce or espagnole sauce
Combine equal parts brown stock and espagnole sauce
Simmer until reduced by about half
Strain again until smooth
Cool and store properly