01 -
Peel and thinly slice the Vidalia onions and shallots. The thinner you slice them, the more quickly and evenly they'll caramelize.
02 -
Remove the peel from the garlic cloves by cutting off the bottom of each clove. Place all cloves in a large bowl, then cover with another bowl of similar size. Shake the bowls vigorously for about 10 seconds. The peels will separate from the cloves like magic!
03 -
Add the olive oil to a Dutch oven or heavy-bottomed pot over medium heat. Add the sliced onions, shallots, and peeled garlic cloves. Cover the pot with a lid.
04 -
Cook the covered mixture for about 20 minutes, stirring occasionally to prevent sticking. During this time, the onions will soften significantly and become translucent as they release their moisture.
05 -
Remove the lid and add the red wine, balsamic vinegar, and brown sugar. Stir well to combine. Continue cooking uncovered for approximately 30 more minutes, stirring occasionally, until the onions develop a rich, caramelized color and the mixture thickens to a jam-like consistency.
06 -
If any large pieces of garlic remain, use a fork to mash them into the jam. Add fresh thyme leaves if using, and season with salt and pepper to taste. Allow to cool slightly before transferring to jars or serving containers.