Step 1

In a large skillet set to medium-high heat. Add the butter and the olive oil. Add in the diced onion and cook until the onions are tender and translucent. Add in the sliced mushrooms and sauté with the onion, stirring frequently until the mushrooms are lightly browned.

Step 2

Add the minced garlic, thyme, salt and pepper. Stir together until the garlic is fragrant then transfer all to a separate bowl.

Step 3

Add red wine vinegar and scrape the bottom of the skillet to deglaze the pan. Continue cooking to allow some of the red wine vinegar to evaporate.

Step 4

Add in the beef broth and simmer until reduced by half.

Step 5

Stir in the heavy cream and add the mushrooms back in. Bring it all to a simmer until the sauce reaches your desired thickness. Season the sauce to taste with more salt and pepper if needed. Serve over your favorite steak.