Preheat the oven to 400°F (200°C) for roasting the potatoes.
Wash the baby potatoes and cut them in halves if they are larger. Toss them gently with olive oil, salt, and pepper, then spread them on a baking sheet.
Roast the potatoes in the preheated oven for about 20-25 minutes or until they are tender and starting to crisp on the edges.
While the potatoes roast, season the top sirloin steak with salt and pepper on both sides.
Heat a cast-iron skillet over medium-high heat and add the steak. Sear for about 3-4 minutes on each side, depending on thickness and desired doneness.
In the final minute of searing, add the unsalted butter, garlic clove (lightly crushed), rosemary, and thyme to the pan. Spoon the melted herb-garlic butter over the steak continuously for added flavor.
Once the steak is seared to your liking, remove it from the pan and let it rest for a couple of minutes.
Plate the steak alongside the roasted baby potatoes. Drizzle any remaining herb butter from the pan over the steak.
Serve immediately and enjoy!