Gather all your ingredients and equipment, and set a large heavy-bottomed pot over medium heat.
Add a tablespoon of oil to the pot and sauté diced onion and minced garlic, stirring often, until fragrant and translucent—about 3 minutes. You should hear a gentle sizzle and smell a sweet aroma.
Add diced carrots and celery to the pot, along with a handful of fermented vegetables. Cook, stirring occasionally, until the vegetables are tender and the fermented veggies are heated through—about 5-7 minutes. The mixture should smell tangy and savory.
Pour in the chicken broth and bring the mixture to a gentle simmer. Once bubbling, add the shredded cooked chicken. Let everything simmer uncovered for 20 minutes, allowing the flavors to meld and the broth to deepen in flavor.
Taste the soup and adjust with salt and pepper as needed. Squeeze in the juice of a fresh lemon to brighten the flavor profile and stir to combine.
Once seasoned and brightened, ladle the hot soup into bowls. Serve immediately, garnished with fresh herbs if desired, with crusty bread on the side. Enjoy the bold, tangy, and comforting flavors in every spoonful.