Quarter the baby potatoes and place them in a large pot of salted water. Bring the water to a boil over medium-high heat and cook until fork-tender, roughly 12–15 minutes. Drain and set aside.

Pat the sirloin steak dry and season with salt and pepper. Heat olive oil in a skillet over high heat. Sear the steak for 2–3 minutes without moving, then flip and cook for another 1–2 minutes. Remove and rest.

In the same skillet, add more olive oil if needed and reduce heat to medium. Place smashed potatoes cut-side down and cook for about 4–5 minutes until golden. Flip and cook for another 3–4 minutes.

Lower heat to medium-low, add butter and minced garlic to the skillet. Sauté garlic for about 1 minute until fragrant. Stir in thyme and rosemary.

Return the steak bites to the skillet, toss to coat, and cook for another 1–2 minutes to heat through. Adjust seasoning if needed.