Heat clarified butter in a saucepot and add mirepoix. Cook over medium heat with frequent stirring until lightly browned.
3
Add the tomato purée to the mirepoix and stir constantly until it achieves a rusty red color.
4
Add the hot stock to the mirepoix and tomato mixture and bring to a simmer.
5
Whisk brown roux into the stock and stir to fully dissolve the roux. Bring mixture back to a simmer.
6
Add the sachet and simmer the sauce over low heat. Stir occasionally to prevent the sauce from scorching. Skim any scum that rises to the top. Cook for 90 minutes or until the sauce reaches nappé consistency.
7
Remove from heat and strain the sauce through a chinois.
8
**Hold at or above 135°F (57°C) or cover sauce with plastic wrap and cool to 70°F (21°C) in two hours or less, and below 41°F (5°C) in less than a total of six hours.