Prepare glaze as directed; cool. Transfer to an airtight container and refrigerate for up to 24 hours. Before glazing the ham, transfer the glaze to a small saucepan. Cover and cook until heated through. Pour over ham and vegetables as directed.
To peel boiling onions, in a medium saucepan, cook onions in boiling water for 30 seconds; drain. Rinse with cold water; drain again. When cool enough to handle, cut a small slice from the root end of each onion. Squeeze from the other end to remove the onion from the peel.