Make ahead: Peel 3 medium onions and chop them finely.
Melt 1 Tablespoon pork lard in a separate sauce pan and set it to medium heat.
Add the onion and stir until it turns lightly golden brown.
Add 1 cup tomato paste, stir about 1 minute.
Pour in ⅔ cup all-purpose flour and stir continuously for 30 sec.
Gradually, add 5 cups beef broth, lukewarm, while still whisking to avoid lumps.
Add salt, ¾ cup granulated sugar, 5 Tablespoons vinegar and spices: 10 peppercorns and 5 allspice.
Bring it to a boil turn down the temperature to a third, and simmer while stirring occasionally for 20 minutes.
Season the tomato gravy with salt and sugar if necessary.
Remove the pan with the sauce from the heat source and strain it through a sieve into a clean pot.
Add 1.½ Tablespoons unsalted butter, cold, to soften up the sauce. Mix with a spoon until butter melts. Do not cook anymore.