Heat olive oil in a large heavy-bottomed skillet over medium-high heat.
Add the cubed potatoes to the skillet and cook for 10 to 12 minutes, stirring occasionally, until golden brown and fork-tender.
Remove the potatoes from the skillet and set aside on a plate.
Increase the skillet heat to high and add the steak cubes in a single layer.
Sear the steak for 2 minutes per side without crowding the pan until a brown crust forms.
Reduce the heat to medium and return the cooked potatoes to the skillet.
Add the butter, minced garlic, oregano, salt, and black pepper to the mixture.
Toss the steak and potatoes for 1 to 2 minutes until the butter is melted and the garlic is fragrant.
Remove from heat and garnish with fresh parsley and red pepper flakes before serving.