Prep the steak: Pat the steaks dry with paper towels. Season both sides with salt and pepper. Let them sit at room temperature for 15 minutes while you prep the mushrooms and aromatics.

Slice the vegetables: Clean mushrooms with a dry towel and slice. Thinly slice the onion or shallot and mince the garlic. Chop the herbs.

Heat the pan: Set a large skillet (cast iron is ideal) over medium-high heat. Add 1 tablespoon oil and heat until shimmering.

Seat the steak: Lay the steaks in the hot pan without crowding. Cook 3–5 minutes per side, depending on thickness, until browned and cooked to your liking. Remove to a plate and tent loosely with foil.

Sauté the mushrooms: Add the remaining oil if the pan looks dry. Add the mushrooms in an even layer. Don’t stir for 2 minutes so they can sear. Then season with a pinch of salt and cook, stirring occasionally, until browned and their moisture evaporates, about 5–7 minutes.

Add onion and garlic: Stir in the sliced onion/shallot and cook until softened, 2–3 minutes. Add the garlic and herbs; cook 30–60 seconds until fragrant.

Deglaze: Pour in the broth and Worcestershire. Scrape up browned bits from the pan. Simmer 1–2 minutes to slightly reduce. For extra depth, add Dijon or a splash of wine now and simmer another minute.

Finish with butter: Turn heat to low and stir in the butter until melted and glossy. Taste and adjust seasoning with salt, pepper, or a squeeze of lemon.

Slice and return steak: Slice the steak against the grain into strips. Return it and any juices to the skillet, tossing with the mushrooms to coat and warm through, about 1 minute.

Serve: Garnish with more herbs if you like. Pair with cauliflower mash, sautéed greens, or a simple salad to keep it low carb.