Crisp the Potatoes: In a large 12-inch heavy cast-iron skillet, heat 1 tablespoon olive oil and 1 tablespoon butter over medium heat. Add the quartered potatoes, cut-side down. Season with half the salt, pepper, and smoked paprika. Cook undisturbed for 5 minutes until deeply golden, then stir and cook for another 10 to 12 minutes until fork-tender and shatteringly crispy on all sides. Transfer potatoes to a plate.

Sear the Steak Bites: Turn the heat up to high. Add the remaining 1 tablespoon olive oil to the hot skillet. Season steak cubes generously with salt, pepper, and onion powder. Add steak bites in a single uncrowded layer. Sear without moving for 2 minutes to form a deep caramelized crust, then flip and sear for an additional 1 to 2 minutes for medium-rare to medium. (Work in two batches if necessary so meat sears rather than steams!).

Make Garlic Herb Butter Glaze: Reduce heat to medium-low. Add the remaining 3 tablespoons butter, minced garlic, fresh rosemary, and fresh thyme to the skillet with the steak. As the butter foams and melts, spoon the fragrant sizzling garlic herb butter continuously over the steak bites for 1 minute.

Toss & Reheat Together: Return the crispy cooked potatoes to the skillet. Toss everything gently together for 1 to 2 minutes so the golden potatoes soak up the rich garlic herb butter drippings.

Garnish & Serve: Remove from heat immediately. Garnish generously with fresh chopped parsley and a pinch of flaky sea salt. Serve sizzling hot right out of the skillet!