Place halved baby potatoes in a large pot of salted water and bring to a boil. Cook for 8-10 minutes until tender but still firm when pierced with a fork. Drain well and let steam dry for 1-2 minutes.

Pat beef cubes dry with paper towels and season generously with salt and pepper on all sides.

Melt 2 tablespoons of butter in a large 12-inch skillet over medium-high heat. Add beef cubes in a single layer (work in batches if needed) and cook undisturbed for 1.5-2 minutes per side until deeply browned. Transfer to a plate.

Add remaining 6 tablespoons of butter to the skillet along with parboiled potatoes, arranging them cut-side down. Cook without stirring for 10-15 minutes until golden and crispy on the bottom.

Add minced garlic, rosemary, and thyme to the skillet. Stir everything together and cook for 1 minute until fragrant.

Return beef to the skillet along with any accumulated juices. Toss everything together gently and cook for 2 minutes to warm the beef through.

Remove from heat and stir in fresh parsley. Taste and adjust seasoning with additional salt and pepper if needed. Serve immediately.