Total prep and cook time: Approximately 30 minutes (10 minutes prep, 20 minutes cook time). Cut the potatoes into small cubes and toss with olive oil, salt, and paprika.
Cook the potatoes in a skillet over medium heat for about 10 minutes until golden and tender, then set aside.
Pat the steak cubes dry, season with salt and pepper, and sear them in butter until browned on both sides.
Remove beef, lower the heat, and melt remaining butter with garlic and rosemary until fragrant.
Return potatoes and beef to the skillet, toss in the garlic butter sauce, and drizzle with Worcestershire if desired.
Garnish with parsley and serve hot.