01 - Pat the sirloin cubes dry with paper towels. Season evenly with kosher salt, black pepper, and smoked paprika.
02 - Heat a large skillet or cast-iron pan over high heat. Add 1 tablespoon of unsalted butter; once melted and foaming, add half the steak cubes in a single layer. Sear for 1 to 2 minutes per side until browned and just cooked through. Transfer to a plate and repeat with remaining steak, adding a little oil if needed.
03 - Reduce heat to medium-low. Add remaining 2 tablespoons unsalted butter and minced garlic to the pan. Cook, stirring, for 30 seconds until fragrant.
04 - Return all steak bites to the pan; toss gently to coat with garlic butter. Stir in chopped fresh parsley and thyme, if using.
05 - Serve immediately, garnished with flaky sea salt and extra parsley, if desired.