Start by cutting your steak into bite-sized cubes and washing your potatoes. If desired, parboil the potatoes for 5 minutes to ensure they cook perfectly. Minced garlic and herbs should be ready to toss with your ingredients.
Lay out heavy-duty foil sheets and place the steak and potatoes in the center. Drizzle with olive oil, season with herbs, and fold the foil to seal the packets tightly. Double layers of foil help prevent leaks.
Place the packets on a preheated grill or in the oven at 400°F. Cook for 25–30 minutes, or until potatoes are tender and steak reaches your desired doneness. Open carefully, as steam will escape.
For extra flavor, open the foil packets and place under the broiler for a few minutes to brown the steak slightly. Keep a close eye so nothing burns.
Carefully transfer the foil packs to plates. Let them rest for a few minutes before eating to allow juices to redistribute.