This hearty soup is easy to make, nutritious, and affordable. Root vegetables lend a sweet earthiness to the soup that combines beautifully with fragrant thyme. A little bit of cream swirled into the soup at the very end of cooking brings it altogether.
Melt the ghee in the bottom of a Dutch oven or heavy stockpot over medium heat, and tip in the onion. Sprinkle the onion with salt and thyme, stir, and then cover the pot. Allow the onions and thyme to sweat in the hot fat for about 5 minutes, or until they soften and release their fragrance.
Dump the celeriac, carrots, parsnips, and turnips into the pot, and then pour in the bone broth. Increase the heat to medium-high. When the contents of the pot reach a boil, turn down the heat to medium, cover the pot, and then simmer the soup for about 25 minutes or until the vegetables are tender.