Cut ends of onion off and peel off outer layer. Cut into 6 thick slices.
Carefully remove the small inner rings, leaving 2-3 outer rings intact.
Wrap the ring groups with a strip of bacon, stretching to fit around the whole circumference and patting ends together to hold.
Place on medium grill, watching carefully, or cook in the oven at 400 F on a foil lined baking sheet for 20 minutes until baking has thoroughly cooked and crisped*
Notes
*cooking time will vary due to the oven or grill and the thickness of the bacon