Making your own vegetable stock can save you money and enhance the dish you are making with flavor.
Keep a plastic container in your freezer, or a zip lock bag. When you are cooking, chopping onions, leeks, celery, mushrooms, carrots etc. don’t throw the trimmings away. Keep a bowl next to you when cooking, and any vegetable trims go into the bowl. Transfer the contents of the bowl into the container that you have in the freezer. When the bag is full, put the contents into a large pot, fill it with water, bring it to a boil and simmer for 30-40 minutes. Then strain the stock. Pour into a freezer container, let cool and freeze.
You can use the cooked trimmings for compost or just throw them away.
Now you have a wonderful stock that is in your freezer to use. You can defrost what you need and put it right back in the freezer.
Trust me and try this, you will become a convert to never tossing your vegetable trimmings away again.