How to Can Caramelized Onions for Long-Term Storage

Canning caramelized onions is a fantastic way to preserve their rich, sweet flavor for future use. If you find yourself with an abundance of onions, like 50 pounds of Spanish sweet onions, this method can save you time and effort in the kitchen later on. Here's a step-by-step guide on how to can caramelized onions, ensuring you always have them on hand for your favorite recipes.

Ingredients and Equipment
50 pounds of Spanish sweet onions
Mandolin slicer or sharp knife
Food processor or dicer (optional)
Slow cooker (6-quart size)
Butter (1 stick)
Roasted garlic powder (1 tablespoon)
Worcestershire sauce (1/2 cup)
Canning jars (half-pint size recommended)
Lids and rings for jars
Pressure canner

Step-by-Step Process
Prepare the Onions: Start by peeling and slicing the onions. Using a mandolin slicer will help you achieve uniform, thin slices. If you don’t have a mandolin, a sharp knife will do the job. For dicing, a food processor can save time.

Caramelize the Onions: Fill your slow cooker with the sliced onions, adding a stick of butter. Set the slow cooker to low and cook for about 8 hours. This can be done overnight for convenience. In the morning, add 1 tablespoon of roasted garlic powder and 1/2 cup of Worcestershire sauce. Stir well and let it cook on warm for a few more hours.

Prepare the Jars: While the onions are caramelizing, sterilize your canning jars. Keep the lids in warm water (not boiling) to soften the sealing compound.

Fill the Jars: Once the onions are ready, carefully fill the hot jars with the caramelized onions, leaving about 1/2 inch of headspace. Ensure that each jar has a good mix of onions and the flavorful broth they’ve created.

De-bubble the Jars: Use a non-metallic utensil to remove any air bubbles from the jars. Wipe the rims of the jars with vinegar or warm water to ensure a good seal.

Seal the Jars: Place the lids on the jars and screw the rings on until they are finger-tight. Be careful not to over-tighten.

Pressure Can the Onions: Place the jars in the pressure canner. Process the jars at 10 pounds of pressure for 70 minutes. This time may vary slightly depending on your altitude, so adjust accordingly.

Cool and Store: After processing, allow the canner to cool and depressurize naturally. Remove the jars and let them cool completely. Check the seals before storing. Any jars that didn't seal properly should be refrigerated and used first.

Using Your Caramelized Onions
These canned caramelized onions are versatile and can be used in a variety of dishes:

Burgers and Sandwiches: Top hamburgers or patty melts with warm caramelized onions.
Roasts and Stews: Add them towards the end of cooking for a rich, sweet flavor.
Eggs: Stir them into scrambled eggs or serve alongside fried eggs for a savory breakfast.
Hot Dogs and Sausages: They make a fantastic topping for hot dogs and sausages, adding depth to the flavor.
Canning caramelized onions not only preserves their flavor but also ensures you have a ready-to-use ingredient for enhancing numerous dishes. Enjoy the convenience and the delightful taste of homemade caramelized onions all year round!