Heat the vegetable oil in a medium saucepan over medium heat until shimmering. Add the finely chopped onion and sauté for 5–7 minutes until soft and translucent.

Stir in the minced garlic and cook for another 1–2 minutes until fragrant.

Pour in the red wine and bring to a simmer. Allow to reduce by half for about 10–15 minutes.

Add the beef broth, Worcestershire sauce, soy sauce, Dijon mustard, fresh thyme, and rosemary. Stir well to combine.

Reduce heat and let the sauce simmer for 15–20 minutes to thicken.

Strain the sauce through a fine-mesh sieve for smoothness, if desired.

Whisk in the unsalted butter until melted, and season with salt and black pepper to taste.

Serve hot over your favorite cooked steak.