Preheat your oven to 400°F.
Rinse and halve the baby potatoes. Toss them with olive oil, salt, and pepper, and spread on a baking sheet.
Roast the potatoes in the oven for around 20-25 minutes, or until golden and tender, stirring halfway through.
Meanwhile, pat the sirloin steak dry and season both sides generously with salt and black pepper.
Heat a heavy skillet over medium-high heat until very hot. Add the steak and sear for about 3-4 minutes per side for medium-rare, adjusting cooking time according to thickness and desired doneness.
In the last minute of cooking, add the unsalted butter, garlic, rosemary, and thyme to the skillet. Tilt the pan slightly and spoon the melted, herb-infused butter over the steak to enhance flavor.
Remove the steak from the skillet and let it rest for a couple of minutes.
Plate the rested steak alongside the roasted baby potatoes. Drizzle any remaining herb garlic butter from the pan over the steak for extra flavor.
Serve immediately and enjoy!