Place quartered baby Yukon gold potatoes in a microwave-safe bowl with 2 tablespoons of water. Cover loosely and microwave on HIGH for 4 to 5 minutes until just fork-tender. Drain well and pat thoroughly dry with paper towels.
Pat beef steak cubes dry with paper towels. Season evenly with kosher salt, freshly cracked black pepper, smoked paprika, and onion powder.
Heat 1 tablespoon olive oil and 1 tablespoon butter in a large heavy cast-iron skillet over medium-high heat until sizzling. Add par-cooked potatoes cut-side down in a single layer. Cook without moving for 3 to 4 minutes until a deep golden crispy crust forms. Toss and cook for another 3 minutes until crisp all over. Transfer potatoes to a warm plate.
Add 1 tablespoon olive oil to the hot skillet over high heat. Add the seasoned steak bites in a single uncrowded layer (sear in two batches if necessary). Sear undisturbed for 2 minutes to develop a dark caramelized crust. Flip and sear for 1 to 2 minutes more for medium-rare to medium tenderness.
Reduce skillet heat to medium. Add remaining 3 tablespoons butter, minced garlic, chopped rosemary, and fresh thyme. As the butter melts and foams, spoon the aromatic herb garlic butter continuously over the steak bites for 60 seconds.
Return the crispy golden potatoes back to the skillet and toss everything together in the foaming garlic herb butter for 1 minute until glazed and piping hot.
Remove from heat immediately to prevent overcooking the steak. Garnish generously with fresh chopped parsley and a sprinkle of flaky sea salt. Serve hot straight from the skillet.