Although caramelized onions take a little time to prepare, they can add a whole new flavor profile to your favorite recipes. Try them on pizza and hamburgers or served alongside your favorite steaks and roasted vegetables.
When prepared in a seasoned cast iron skillet, the onions will turn a dark caramel color that is next to impossible to achieve with a regular non-stick pan.
2 or 3 large yellow onions
2 tablespoons unsalted butter
2 tablespoons extra virgin olive oil
1/3 cup balsamic vinegar
With a sharp knife, remove both ends of onion and cut in half lengthwise. Turn one piece of onion onto flat side and cut into thin slices, working from one end to another. Repeat until all onions are sliced.
Melt butter in cast iron skillet over medium heat. Add onion slices to skillet and drizzle olive oil over the top. Sprinkle with salt, if desired.
Slowly cook the onions down over medium heat for 45 minutes to an hour. (Total cooking time will depend on how many onions were used, the onions’ sugar content, and how old they are).
Stir the onions every 5 or 10 minutes while they are cooking to prevent scorching.
Once the onions are done caramelizing, add balsamic vinegar to deglaze the pan. While the liquid is bubbling, gently scrape the bottom of the pan to incorporate the fond or brown bits on the bottom of the pan into the onions.
Season with additional salt, if desired. Use immediately, or cool and store in the refrigerator for up to one week. Caramelized onions can also be frozen and stored for a couple of months.