Mushroom Sirloin Recipe

Prepare and Marinate

Pat the sirloin steak dry with paper towel. In a small bowl whisk together 2 tbs olive oil, 1 tbs soy sauce, 1 tsp Worcestershire sauce, 2 tsp minced garlic, 1 tsp black pepper and 1 tsp kosher salt. Rub the marinade all over the steak, place in a shallow dish or zip-top bag and refrigerate for at least 30 minutes and up to 2 hours (bring to room temperature 20–30 minutes before cooking).

Sear the Steak

Heat a heavy skillet (cast-iron preferred) over medium-high heat until very hot. Add a thin film of oil or a little butter. Remove excess marinade from the steak and place steak in skillet. Sear without moving for 3–4 minutes to develop a deep brown crust (for about 1-inch thick steak). Flip and sear 3 minutes for medium-rare (internal temp 125–130°F / 52–54°C). Adjust time for thickness and desired doneness. Transfer steak to a plate, tent loosely with foil and let rest 5–10 minutes while you make the mushroom sauce.

Cook Mushrooms

While steak rests, wipe the same skillet if it has burnt bits but keep fond (do not wash). Add 1 tbs olive oil and 2 tbs butter over medium-high heat. When butter foams, add sliced cremini and shiitake mushrooms in a single layer. Let them sear without crowding or stirring for 2–3 minutes, then stir and cook until they release moisture and brown, about 4–6 minutes total.

Aromatics

Push mushrooms to the side. Add the finely chopped shallot and 1 tsp minced garlic to the pan and cook 30–45 seconds until fragrant but not browned.

Deglaze & Reduce

Pour in 1 tbs dry red wine (or sherry) to deglaze the pan, scraping up browned bits with a wooden spoon. Let the wine reduce for 1 minute.

Build the Sauce

Stir in 3 tbs beef stock, 1 tbs heavy cream, 1 tsp Dijon mustard and 1 tsp fresh thyme. Simmer gently until sauce thickens slightly, about 2–3 minutes. Taste and season with up to 1 tsp salt and 1 tsp black pepper as needed. If sauce becomes too thick, add up to 1 tbs more stock.

Finish & Serve

Stir in 1 tbs chopped fresh parsley and remove from heat. Place the rested sirloin on a cutting board, slice against the grain into 1/4–1/2-inch slices, arrange on serving plates, and spoon the warm mushroom sauce over the steak. Serve immediately.