In a large pot, heat 1 tablespoon of olive oil over medium heat. Add the finely chopped lemongrass, chopped onion, grated ginger, and minced garlic. Sauté for about 3-4 minutes until the onion becomes translucent and the kitchen fills with a fragrant aroma.
Pour in 3.5 cups of vegetable broth or water, stirring to combine. Add the Thai red curry paste and mix until fully dissolved in the liquid. Bring the mixture to a gentle simmer.
Once the broth is simmering, add the spiralized sweet potato, zucchini, and celery root to the pot. Stir well to ensure the vegetables are covered in the broth and cook for about 5-7 minutes, or until the vegetables are tender yet still have a slight crunch.
Reduce the heat to low and pour in the full-fat coconut milk. Stir to combine thoroughly and let the soup simmer for an additional 3-5 minutes. This will enrich the flavors and create a creamy texture.
Add the juice of 1/2 lime to the pot, seasoning with salt and pepper to taste. Serve your soup hot, garnished with torn fresh basil and a sprinkle of fresh cilantro if desired. Don’t forget extra lime wedges on the side for an added zesty kick!
