Prep mashed potatoes: Place quartered Yukon gold potatoes in a pot of cold salted water. Bring to a boil and cook for 15-18 minutes until fork-tender. Drain well, return to hot pot, and mash with warm cream, 3 tablespoons butter, and salt until velvety smooth. Cover to keep warm.

Season steak bites: Pat steak cubes completely dry with paper towels (moisture prevents a crust!). Toss in a bowl with garlic powder, onion powder, smoked paprika, coarse kosher salt, and cracked black pepper.

Smoking-hot sear: Heat 2 tablespoons oil in a large cast-iron skillet over high heat until just smoking. Add steak bites in a single layer without crowding (cook in two batches if necessary).

Hard sear: Cook undisturbed for 2 minutes to develop a deep caramelized brown crust. Flip and cook for another 1-2 minutes until browned on all sides (keep medium-rare to medium, internal temp ~135°F / 57°C). Transfer steak bites to a clean plate.

Make garlic herb butter: Reduce heat to medium-low. Add 4 tablespoons butter to the skillet. Once foaming, add minced garlic, fresh rosemary, and fresh thyme. Sauté for 60 seconds until fragrant, swirling the pan to scrape up the caramelized brown steak fond.

Toss and baste: Return the steak bites and any accumulated resting juices back into the skillet. Spoon the foaming garlic herb butter generously over the steak for 1 minute until glistening and thoroughly coated.

Assemble & serve: Spoon warm mashed potatoes onto plates. Pile juicy caramelized steak bites right alongside. Drizzle remaining pan garlic herb butter lavishly over both steak and potatoes. Garnish with fresh chopped parsley. Serve immediately!