I suggest you find small red onions for this if you intend on putting them on a plate with other food items. Large onions would dress up a a serving platter quite nicely though.Found the recipe in a LCBO magazine called "Food and Drink" (LCBO = liquor control board of Ontario). Cut onion in half down to about 1/2 inch of the root end but not through. Cut onions in half again and again crosswise to 1/2 inch of the root. Cut each quarter in half again but not through to the root. There should be 8 wedges attached at the bottom like a flower bud.Place the onions in a bowl and gently toss with olive oil and balsamic vinegar. Season with salt and pepper. Grease a baking dish large enough to hold the onions with plenty of space around them to open up completely.Cover with foil and bake at 425F for 25 to 30 minutes until onions have opened up and are nearly tender.Uncover and bake for 10 minutes more, serve with a sprinkling of capers if desired.song and music by Jason Shaw (audionautix) vocals by rosettachan