Preheat oven to 400°F (200°C).
Toss halved baby potatoes with olive oil, rosemary, salt, and pepper on a baking sheet.
Roast potatoes for 25 to 30 minutes until fork-tender and edges are crisp.
Season room-temperature steaks generously with salt and pepper.
Heat a cast-iron skillet over high heat and sear steaks for 3 to 4 minutes per side to achieve a Maillard crust.
Remove steaks from skillet and allow to rest for 5 minutes.
Reduce heat to medium, melt butter in the skillet, and sauté minced garlic for 60 seconds.
Deglaze with beef broth and whisk in heavy cream, simmering until the sauce reduces by one-third.
Plate the steaks and potatoes, drizzling the creamy garlic butter sauce over the meat, garnished with fresh parsley.
