Gather all ingredients, peel and chop the carrots and bell pepper, mince the garlic, and dice the onion. Prepare the shredded cooked chicken and bruise the lemongrass stalks to release their aroma.
Heat a large pot over medium heat and add a splash of oil. Once shimmering, sauté the diced onion until translucent and fragrant, about 3-4 minutes.
Add the minced garlic and grated ginger to the pot, cooking until fragrant, about 1-2 minutes. Then, add the bruised lemongrass stalks and stir for another minute to release their aroma.
Stir in the chopped carrots and bell pepper, cooking for about 5-6 minutes until they start to soften and release their bright colors and aroma.
Pour in the chicken broth and bring the mixture to a gentle simmer. Skim off any foam that rises to the surface as it begins to bubble.
Add the shredded cooked chicken to the broth, stirring gently to combine. Squeeze in the fresh lemon juice and season with salt and pepper to taste.
Reduce the heat to low and let the soup simmer uncovered for about 20 minutes, stirring occasionally. The vegetables should become tender, and the broth will develop a fragrant, clear appearance.
Taste the soup and adjust seasoning as needed, adding more salt, pepper, or lemon juice for brightness.
Remove the lemongrass stalks before serving to avoid overpowering flavors. Ladle the hot soup into bowls, ensuring each serving has a good mix of vegetables and chicken.
Serve the soup hot, garnished with fresh herbs if desired. Enjoy the bright, aromatic flavors that make this dish a comforting yet invigorating meal.
