For the mashed potatoes:

1. Cook the potatoes:
   • Place the peeled and cubed potatoes in a large pot and cover with cold water. Add a generous pinch of salt. Bring to a boil over medium-high heat and cook for 15–20 minutes, or until the potatoes are fork-tender.
2. Mash the potatoes:
   • Drain the potatoes and return them to the pot. Add the butter and warmed milk or cream. Mash until smooth and creamy. Season with salt and pepper to taste. Cover and set aside.

For the steak:

1. Prepare the steak:
   • Remove the steaks from the refrigerator 30 minutes before cooking to allow them to come to room temperature. Pat dry with paper towels and season both sides generously with salt and black pepper.
2. Sear the steak:
   • Heat a cast-iron skillet or heavy-bottomed pan over medium-high heat until very hot. Add the olive oil and let it shimmer.
   • Place the steaks in the skillet and cook without moving for 3–4 minutes (for medium-rare), or until a crust forms. Flip and cook for another 3–4 minutes.
3. Add butter and aromatics:
   • Lower the heat to medium. Add the butter, smashed garlic, and rosemary or thyme to the skillet. Tilt the pan slightly and use a spoon to baste the steaks with the melted butter for 1–2 minutes.
4. Rest the steak:
   • Remove the steaks from the skillet and let them rest on a plate for 5–10 minutes to allow the juices to redistribute.

Assemble and serve:

• Plate the mashed potatoes and top with a steak. Drizzle the steak with any remaining butter from the pan or serve with a simple pan sauce if desired. Add a side of steamed vegetables or a fresh salad for a complete meal.