Preheat oven to 250 degrees F.
Cut off a small portion (approximately 1/4-inch) off the bottom or root end of each onion. This is to steady the onions in the baking dish.
Place whole onions into a baking dish with approximately one inch of water. Bake, uncovered, approximately 2 hours or until onions are soft when you squeeze them.
Remove from oven and place onto a cutting board; pull back brown skins and cut them off at the roots. Transfer onto a serving platter and season each with salt, pepper and 1 teaspoon butter.
For an extra-special taste sensation, drizzle the tops (or use a dropper) of each baked onion serving with balsamic vinegar. So good!
* Some U.S. sweet and mild onion varieties (available in the spring/summer) have a similar sugar content (or sometimes even less sugar) than the storage varieties. Naturally, we don't always taste that difference due to both water and sulfur content present in a raw onion; however, we can often taste those differences when onions are cooked!
Look for sweet onions that are light golden-brown in color, with a shiny tissue-thin skin and firm, tight, dry necks. (Ordinary storage onions are darker and have a thicker skin.) When cut into, sweet onions should have a creamy white interior. Avoid onions that have soft spots or surface bruises.
Baked Sweet Onions Recipe: https://whatscookingamerica.net/Vegetables/bkdswton.htm