The recipe I used is long gone but it's super easy, actually.

Just cut the onion in rings like you'd do normally. Keep the nice big ones.

Brush some sriracha on them onions.

Roll the bacon on the rings. I use wood skewers to hold them in place but that's not mandatory.

Personally I baked them in the oven for 30 min at 350F, then pumped it up to 425F when I decided it was too long, for another 20 minutes. (edit: make sure to check them regularly if you use this temp!)

You can also grill them at low heat.

If you bake them in the oven, you can also dip the rolled-up onion bacon ring in some brown sugar just before cooking it, for added flavor (watch out though, it'll burn faster). On the grill you'd be better off brushing some honey on it instead.

Good luck!