Tear off 6 large square sheets of aluminum foil. Drizzle all 6 aluminum pieces with olive oil. Put 1 tablespoon of butter on each foil sheet.
Divide up the potatoes and place on top of the butter on each aluminum foil square. Evenly sprinkle garlic and onion over each of the servings. Then sprinkle with salt and pepper to taste.
Drizzle with a bit more olive oil. Put steak on top of potatoes. Sprinkle with steak seasoning. Drizzle with olive oil. Fold sides up making squares and seal so nothing will escape.
Preheat grill to 350 degrees. Grill packets for 40 minutes and open being careful to let out the steam.