All onions change consistency and texture when frozen, and pearl onions--small onions harvested long before maturity--are no different. Yet, for onions you add to recipes such as stews or soups, or to other cooked vegetables, the differences are negligible. The key to successfully freezing pearl onions is to do it quickly after the harvest. Pearl onions are often gathered in the fall before the first frost.
Things You'll Need
Zipper freezer bags
Clean the pearl onions as if getting ready to eat them. Remove the green stalks, root ends and outer skins.
Place the cleaned pearl onions in a single layer on a cookie sheet. The onions can touch, but make sure they remain in one even layer.
Cover the cookie sheet with plastic wrap. If you do not have plastic wrap, you can use aluminum foil.
Place the wrapped cookie sheet in the freezer, taking care to put them where the pearl onions will remain level in the pan.
Freeze for 12 hours or overnight, until the pearl onions are completely frozen. Remove the frozen onions from the pan and quickly repackage them into zipper freezer bags and place in the freezer.
When packaging the pearl onions in freezer bags, pack according to portion sizes. For example, if you need a half pound for a stew recipe, pack a bag that weighs that amount. Press out as much air as possible from the freezer bags before placing them back into the freezer. This will help prevent freezer burn. Use the green stalks of pearl onions in the same way you would use the stalks of small green onions. Chopped fine, they make a good seasoning for salads, soups, stews and other recipes. In most cases, pearl onions can go straight from the freezer into the recipe. There is no need to thaw the onions first.