Learning how to freeze chopped onions is really a matter of knowing how you are going to store them. Onions tend to freeze in clumps, so you can go out of your way to freeze them in specific clumps or flash freeze them and avoid the clumps altogether.
Can You Freeze Chopped Onions
Cut off the root and peel the outer skin off of the onion. Dice the onion as you normally would.
Onions have their own juices, so it can be hard to cut and freeze them all together without them sticking together. If they do stick together, all you need to do is hit the bag on the counter to break them up. You can also flash freeze them and avoid the problem. To flash freeze onions or anything else, just lay the cut pieces on a cookie sheet or plate and place them in the freezer. When the pieces are frozen, quickly scrape them off the plate or sheet into a freezer bag or other container.
Freeze in Clumps
If breaking frozen chopped onions apart doesn’t bother you, just dice the onions and place them in a freezer bag before putting them in the freezer. Break off chunks as needed or hit the bag against the counter to loosen the pieces.
Freeze in Serving Sizes
You can also freeze chopped onions in serving sizes. To do this, you just need to find a container of the right size. Muffin tins work well for this and so do ice cube trays. For larger portions, use a jumbo muffin tray. All you need to do is fill the cavity with onions and put the tray in the freezer. The chopped onions will freeze in the shape of a cube or a muffin. Pop them out and place them in a freezer bag or other container. Mark the bag so you know the number of onions you have in the bag. You can save more than one cube or “muffin” in a bag, but you may want to keep the same sizes in the bag so as to avoid confusion when you want to get the appropriate serving out.
When you freeze cubed onions, save them for use in stews and like items. Fresh onions work better when using them to brown meat or make an onion gravy. This means that when you make your chilli, use fresh onions when you brown the ground beef, but feel free to add frozen diced onions to the soup of the chilli.