Preheat the oven to 325°F (163°C).
Heat 2 tablespoons of butter in a large oven-safe skillet over medium-high heat.
Add the halved baby potatoes, onion powder, ¼ teaspoon salt, and black pepper. Toss to coat.
Arrange the potatoes cut-side down and cook undisturbed for 1–2 minutes until lightly browned.
Continue cooking for another 4 minutes, stirring occasionally, until the potatoes begin to soften.
Transfer the potatoes to a baking sheet and roast in the oven while preparing the steak.
Carefully wipe out the skillet.
Melt 1 tablespoon butter over medium-high heat.
Add the steak cubes in a single layer and season with the remaining salt.
Sear the steak for 4–5 minutes, turning occasionally, until browned on all sides and cooked to your preferred doneness.
Reduce the heat to low.
Add the remaining tablespoon of butter, minced garlic, and fresh thyme. Stir for about 30 seconds until fragrant.
Remove the potatoes from the oven and return them to the skillet.
Toss everything together until the potatoes are coated in the garlic butter sauce.
Sprinkle with fresh parsley and serve your Garlic Butter Steak Bites with Crispy Potatoes immediately.