Toss the quartered potatoes with 1 teaspoon of olive oil, salt, and pepper on a baking sheet. Roast at 400°F (200°C) for 15 minutes until slightly softened.
While potatoes roast, season the steak cubes generously with salt, pepper, rosemary, and thyme.
Heat the remaining 1 tablespoon of olive oil in a large, oven-safe skillet over medium-high heat. Add the steak cubes in a single layer, being careful not to overcrowd the pan. Sear for 2-3 minutes per side until browned. Remove steak from the skillet and set aside.
Reduce the heat to medium. Add the butter to the same skillet. Once melted, add the minced garlic and cook for about 1 minute until fragrant. Do not let the garlic burn.
Return the partially cooked potatoes to the skillet with the garlic butter. Toss to coat.
Place the seared steak bites back into the skillet among the potatoes.
Transfer the entire skillet to the 400°F (200°C) oven and bake for an additional 5-8 minutes, depending on your desired steak doneness (5 minutes for medium-rare).
Remove from the oven. Sprinkle with fresh parsley before serving directly from the pan.
Notes
For best results, use a cast iron skillet that can safely move from stovetop to oven.
If you prefer softer potatoes, boil them for 5 minutes before tossing them with oil and roasting.
Adjust the cooking time in the oven for your preferred steak doneness.