Posted: 04/09/2013 at 11:38
Yes, you can freeze them but, thawed, they will be mushy because of their high water content. They won't fry to crispness, for example, but they're fine added during cooking.
Peel them, chop them. Then you have two options.
1. Spread them out on a tray on some baking paper, put the tray into the freezer till they're frozen, then transfer them, frozen, into freezer bags. Extract as much air from the bags as possible, tie them up tightly, label them and put them in the freezer. This method avoids ending up with one big lump of frozen onions.
2. Put the chopped onion straight into freezer bags, extract as much air as possible, tie them up tightly, etc, put them in the freezer. But they will freeze in one lump.