cut potatoes in half and use the Mellon baller or a grapefruit spoon to scoop out a small pocket in each half of the potatoes.
stuff the pockets with the diced onion, sprinkle with salt and pepper to taste,Italian seasoning if using and put 1 1/2 teaspoons of olive oil on each potato half. Put the potatoes halves back together and wrap with foil to seal.
put potatoes on the hot grill or in oven for about an hour or until a fork pierces the potatoes easily.
serve still wrapped in foil and let them open their own potato so they stay warm.