Heat 1 tablespoon olive oil and 2 tablespoons butter in a large skillet over medium-high heat. Add the halved potatoes, season with salt, pepper, thyme, and rosemary. Cook for 10-12 minutes, stirring occasionally, until potatoes are golden and fork-tender. Remove to a plate and set aside.

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

In the same skillet, add 1 tablespoon olive oil and heat over high heat. Add the steak bites in a single layer (work in batches if needed to avoid overcrowding). Sear for 2-3 minutes without moving, then flip and cook another 1-2 minutes for medium-rare.

Reduce heat to medium and add the remaining 2 tablespoons butter and minced garlic to the skillet. Stir for 30 seconds until fragrant, coating the steak bites in the garlic butter.

Return the cooked potatoes to the skillet and toss everything together in the garlic butter for 1-2 minutes until heated through.

Remove from heat, sprinkle with fresh chopped parsley, and serve immediately while hot.