Directions

1. Prep the onions: Trim off the ends and, sliced lengthwise to the center (as if you are slicing it in half lengthwise (vertically, like the Prime Meridian), but only go halfway through). Remove the skin.
2. Fill a large pot halfway with water and bring to a boil. Using a slotted spoon, immerse the trimmed onions into the boiling water. Partially cover pot and gently boil onions for 20 minutes. Using the slotted spoon, transfer onions into a large bowl filled with cold water. Pour out heated water and refresh with more cold water. Let onions cool in the water for a few minutes. To keep from burning your hands, work under water to gently separate the softened outer layers of each onion. Put onions layers in a strainer to dry and set aside.
3. Preheat the oven to 350F.