01 - Pat steak cubes dry with paper towels. Toss with olive oil, salt, and pepper in a bowl. Set aside.
02 - Heat olive oil in large skillet over medium-high heat. Add mushrooms, season with salt and pepper, sauté 4-5 minutes until golden and tender. Transfer to plate.
03 - Increase heat to high. Add steak cubes in single layer, cook in batches if needed. Sear 2-3 minutes, turning to brown all sides. Avoid overcrowding pan.
04 - Reduce heat to medium. Push steak to side. Add butter and garlic to empty space. Sauté garlic 30 seconds until fragrant, then combine with steak.
05 - Return mushrooms to pan. Add parsley, thyme, and red pepper flakes. Toss together 1-2 minutes to coat in garlic butter and heat through.
06 - Remove from heat. Garnish with extra parsley and serve immediately.