Slice the carrots in half lengthwise and then in half or thirds the short way.
Slice onion in half, then each half in thirds.
Slice potatoes in half the long way, then in half again.Then slice in half or thirds the short way.
In a medium bowl mix oil and vinegar.
Add vegetables and toss well to coat. Add oregano.
To Grill on barbecue: Put into ‘grill pan’ (a metal or foil pan dedicated to use on the grill) or onto a mesh grill pan (the idea is not to have the stuff fall through the grate into the fire — ) Cook over medium heat 40-45 minutes, until vegetables have a nice color and potatoes are done.Serve.
To Roast in oven:Put vegetables on a baking sheet with a lip or in a shallow roasting pan.Bake in 420F (215C) oven for 40-45 minutes or until done, stirring occasionally.Vegetables should be lightly browned and tender.Remove, sprinkle with sea salt and serve.