01 - Pat the steak cubes dry with paper towels. Season evenly with salt and pepper.
02 - Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add mushrooms and sauté for 4–5 minutes, stirring occasionally, until browned and tender. Remove mushrooms from the skillet and set aside.
03 - In the same skillet, add 1 tbsp olive oil and 1 tbsp butter. Once hot, add the steak bites in a single layer, cooking in batches if necessary to avoid overcrowding. Sear for 2–3 minutes without stirring, then flip and cook for another 2 minutes until browned and cooked to your desired doneness.
04 - Add remaining butter and garlic to the pan. Stir and cook for 1 minute until fragrant.
05 - Return mushrooms to the skillet. Add parsley, thyme, and chili flakes if using. Toss everything together to coat with the garlic butter. Serve immediately, garnished with extra parsley if desired.