Simple but unique...
One medium to largish potato for each guest. One large green pepper and one or two large yellow onions.
Place the potatoes in the microwave... set the timing for about 3 minutes per potato. Cook until just barely fork tender... not done though.
Slice the potatoes into thick slices at least 1/2 inch. Place them in a double layer of aluminum (Oh... OK, for you Brits, aluminium ). Slice the onions and green pepper equally as thickly and place in the pouch of foil along with three or four pats of butter, salt, pepper and a little (maybe teaspoon) of celery salt... roll top of foil together tightly and place in 350 (F) degree oven for about 40 minutes. Even better if you can do them on a grill about 50 minutes at medium temp.
Plebeian but great taste!