Preheat your oven to 400°F (200°C).

In a large bowl, toss the halved baby potatoes with olive oil, salt, and pepper. Spread them out in a single layer on a baking sheet.

Roast the potatoes in the preheated oven for about 20 minutes, or until they start to become tender.

While the potatoes are roasting, heat a large skillet over medium-high heat. Add 2 tablespoons of butter and let it melt.

Season the beef cubes with salt, pepper, thyme, and rosemary. Add the beef to the skillet in a single layer and sear for about 2-3 minutes on each side until browned.

Once the beef is browned, add the minced garlic and the remaining 2 tablespoons of butter to the skillet. Cook for an additional 2 minutes, stirring frequently, until the garlic is fragrant.

After the potatoes have roasted for 20 minutes, remove them from the oven and add the beef mixture on top. Return the baking sheet to the oven and roast for an additional 10-15 minutes, or until the potatoes are golden brown and the beef is cooked to your desired doneness.

Remove from the oven and garnish with fresh parsley before serving.