Directions

1. 1

   Pour the vegetable oil into a large, heavy-bottomed pot. Using a mandoline slicer, hold each onion by the root end and carefully slice directly into the pot, discarding the root portion. Once all onions are sliced, sprinkle the salt over them and stir well to combine.

2. 2

   Place the lid on the pot and set the heat to medium-low. Cook covered for 45 to 60 minutes, stirring periodically. The onions should gradually break down into a pale brown, soft mass. If you notice any burning on the bottom, reduce the heat and add a small amount of water.

3. 3

   Remove the lid and continue cooking over medium-low heat for another 45 to 60 minutes, stirring every few minutes. This stage allows remaining moisture to evaporate. Watch carefully to prevent burning and adjust heat as needed.

4. 4

   Once most of the moisture has evaporated, begin stirring the onions constantly and scrape the bottom of the pot regularly with a silicone spatula. Continue cooking until the onions become very glossy and reach a rich caramel color, similar to milk added to coffee.

5. 5

   If the onions begin to scorch on the bottom before reaching full caramelization, deglaze the pot by adding a small splash of water and scraping up the browned bits from the bottom with your spatula.

6. 6

   When the onions are fully caramelized, remove from heat and let cool to room temperature. For storage, spoon the cooled onions into an ice cube tray and freeze until solid. Once frozen, transfer the cubes to a freezer bag for easy portioning and long-term storage.