Heat a large cast-iron skillet over medium heat for 2–3 minutes.
Add 1 tablespoon olive oil and 1 tablespoon garlic herb butter.
Once melted, add the cubed Yukon Gold potatoes.
Season potatoes with ½ teaspoon garlic powder, ½ teaspoon salt, and ½ teaspoon pepper.
Reduce heat to medium-low and cover the skillet.
Cook for 10–12 minutes, stirring occasionally, until potatoes are golden brown and fork-tender.
While potatoes cook, season the steak cubes with the remaining garlic powder, salt, and pepper.
Once potatoes are cooked, move them to one side of the skillet.
Add the remaining olive oil and garlic herb butter to the empty side.
Increase heat to medium-high.
Add steak bites in a single layer.
Sear for 3–4 minutes per side until browned and cooked to your preferred doneness.
Avoid overcrowding the skillet; cook in batches if necessary.
Reduce heat to medium-low.
Toss steak bites and potatoes together.
Add extra garlic butter if desired and stir until everything is coated.
Taste and adjust seasoning as needed.
Serve immediately while hot.