In a pre-heated pan, add olive oil. Then, add the onions and the kosher salt.
Sauté the onions for 5 minutes and also toss with tongs.
Cover the pot with a lid on the pot and cook the onions for 5 minutes.
After 5 minutes, remove the lid and toss the onions. Cover the pot again and repeat this step every 5 minutes for15 minutes.
At the fifteen minutes, pour half of chicken broth to the pan. Scrape down bottom of the pan using a sautéing spoon and cover the pan with a lid again.
Cook the onions for another 5 minutes. Then, add the remaining half of the chicken broth and put on the lid.
Cook with a lid on for another 5-10 minutes until the onions are a richly brown and completely caramelized.