I have some plastic containers but I favor the idea of using the sections of my muffin tin. Is it a good, safe way or should I use something else?
You could use a muffin tin, but those would be really small portions. However, if that's what you want I would line the tin with silicone muffin cups. They will make the soup easy to remove from the pan once frozen and the silicone cups will peel right off the frozen soup.
I don't have a microwave, either. I defrost most of our food in the fridge, but if I need to defrost meat in a hurry I use a container filled with cold running water. Leave the meat in its package and place it in a large container in your sink. Fill the container with cold water and then allow the faucet to continue to slowly run cold water into the container. It will defrost most things in an hour or less (while still keeping it at a safe temp). For soups--especially broth based soups--you can just put the frozen block of soup directly into a saucepan on the stove and heat it until it melts.
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