- 1
Remove steak from the fridge 15 minutes before cooking. Pat dry and season all over with salt, pepper, and garlic powder.
- 2
Heat a cast-iron skillet or grill pan over high heat until very hot. Add 1 tbsp olive oil, then lay the steak in the pan. Sear 2–3 minutes per side for medium-rare. Remove and let rest on a cutting board for 5 minutes.
- 3
While the steak rests, lower heat to medium-high in the same pan. Add 1 tbsp butter and the sliced mushrooms in a single layer. Don't stir for the first 2–3 minutes — let them brown. Once golden, stir and cook 2 more minutes. Season with a pinch of salt. Remove mushrooms and set aside.
- 4
In the same pan, add 1 tbsp butter and the sliced onions. Cook over medium heat, stirring occasionally, for 8–10 minutes until softened and golden brown. Add minced garlic and cook 1 more minute.
- 5
Return mushrooms to the pan, stir to combine with onions and garlic. Add Worcestershire sauce if using. Keep warm on low heat.
- 6
Slice the steak thinly against the grain. Fan the slices on a plate and top with the mushroom-onion mixture.
- 7
Finish with a small pat of butter over the hot steak, scatter fresh cilantro leaves on top, and serve with lime wedges on the side.