Preheat a cast iron skillet over medium-high heat. Introduce the olive oil along with 2 tablespoons of butter, allowing it to melt fully.
Add the diced potatoes, minced garlic, rosemary, oregano, salt, and pepper to the skillet. Let them cook undisturbed for about 4 minutes. Stir and continue cooking for an additional 3 to 4 minutes until the potatoes become tender when pierced with a fork. Remove them from the skillet and set aside.
Increase the heat to high and return the skillet to the stove. Add the remaining 2 tablespoons of butter and allow it to melt. Place the steak pieces into the skillet in a single layer. Sear for 1 minute without moving, then flip or stir and cook for another 1 to 2 minutes, or until they reach your preferred level of doneness. Remove the skillet from the heat.
Return the cooked potatoes to the skillet and gently toss with the steak to combine. Season further with salt and pepper to taste.
Garnish with freshly chopped parsley if desired. Serve immediately.