Cook potatoes in microwave oven about 8 minutes on high. Let stand to handle, 5 minutes. Coarsely chop the potatoes.
Heat the EVOO and butter in a nonstick skillet over medium-high heat. When hot, add potatoes to the skillet. Grate the onions over the skillet with a hand held grater on the large side. Toss the potatoes and onions to coat evenly in hot oil and butter and season with grill seasoning. Brown and crisp the potatoes and onions 6-7 minutes. Serve hot alongside chicken and egg sammies.