How can I prepare onions and keep for home hot-dogs, as available from vans?

[solvitquick]

Despite food advice I love hot-dogs: can buy canned hot-dog sausages, soft rolls and have tomato sauce but those onions?

[grasscarp]

Whats wrong with slice them up and fry them on the day?

[solvitquick]

Nope, ty, grasscarp, they seem to be boiled.

[B00]

Slice them, freeze them, then take them out as and when needed and boil them?

[grasscarp]

Oh I see. I thought you meant you wanted to prepare in advance for on the day. If I do home hot dogs I just fry my onions.

[Old_Geezer]

As far as I can see you are quite right, you need to boil them.
Personally I prefer fried.

[jamesnan]

Gently fry in a very little oil for about 15 mins or so, and then add a tiny drop of water and allow it to simmer away. Stirring all the time.

[giveup]

I've just fried 2 kilos this evening for hot dogs at a coffee morning tomorrow. (The house stinks of onions,my hair probably stinks as well) I just intend to refry them when needed.

[lovesgreece]

Having done a few school bbqs, we bought the onions in bulk, sliced and shrink wrapped. You then just put them in a foil dish on barbie, so they sort of fry/steam.