Melt the fat in a heavy saucepan and cook the carrot and onions until lightly browned. Stir in the flour and continue cooking until the flour is browned, stirring continuously.
Add 3 cups boiling stock [can substitute Better Than Bouillon beef base], the garlic and the garlic, celery, parsley and bay leaf tied in a bundle.
Cook and stir over medium heat until the mixture thickens. Add 3 more cups of hot beef stock.
Cook over low heat, stirring occasionally, for 1 hour. Skim off the fat as it floats to the surface.
Stir in the tomato puree and cook 10 minutes. Strain through a fine sieve.
Add the remaining 2 cups of hot stock and cook slowly over low heat for 1 hour. Skim as needed. At this point, the sauce should be reduced to about 4 cups. Strain and cool again.
Store, covered in the refrigerator. Use within 8-9 days
Can substitute pork fat for beef fat.
For glace de viande: bring 4 quarts veal broth [can substitute chicken broth] into a heavy pot or Dutch oven and bring to boil over a low heat and then simmer for 2 hours until only about 1 quart of broth remains. Strain broth into a small saucepan and continue to simmer over low heat until the liquid remaining in the saucepan is brown in color and of a syrupy consistency. Strain into a bowl or jar and refrigerate to use as needed.