In a medium saucepan over medium heat, melt the butter, drippings or any combination of the two. Whisk in the flour, making a paste. Allow to brown for 3-4 minutes.
While whisking, add the red wine to deglaze. Then whisk in the beef broth until smooth. Add the Worcestershire sauce, mustard, black pepper, thyme and rosemary. Bring to a low simmer for 5-10 minutes.
Au jus should be thick enough to coat the back of a wooden spoon, but still a liquid and sauce (not as thick as gravy). If it is too thick, add a small amount more of water, beef broth or wine. If it isn't thick enough, continue to reduce.
Pour the liquid through a fine mesh sieve, discarding any solids.
Serve smooth sauce with desired meal.
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