Preheat your grill to medium-high heat (about 400 degrees F) or your oven to 425 degrees F. Tear off 4 large sheets of heavy-duty foil, about 12 by 18 inches each. Lightly oil the center of each sheet to prevent sticking.

In a small bowl, whisk together the melted butter, minced garlic, chopped parsley, thyme, and Worcestershire sauce. Set aside.

In a large bowl, combine the steak cubes and halved potatoes. Drizzle with olive oil and season with salt and pepper. Toss until evenly coated.

Divide the steak and potato mixture evenly among the 4 foil sheets, mounding it in the center. Drizzle about 1 tablespoon of the garlic butter over each packet, reserving a little for serving.

Fold the long sides of the foil up and over the filling, then fold down twice to seal. Fold in the short ends and crimp tightly to create a sealed packet. Leave a little air space inside for steam to circulate.

Place packets on the grill or a baking sheet in the oven. Cook for 20-25 minutes, flipping once halfway through, until potatoes are fork-tender and steak reaches your desired doneness. Open carefully - steam will escape.

Transfer contents to plates or serve straight from the foil. Drizzle with remaining garlic butter and sprinkle with extra chopped parsley.