This soup packs in all the ingredients that would make your doctor happy (Lentils! Sweet potatoes! Leafy greens!) but is bolstered by fiery Thai green curry paste to keep things interesting. Store-bought Thai curry pastes can vary widely in flavor and intensity from brand to brand (we tested this recipe with Maesri), so there are also lots of aromatics like onion, ginger, and garlic to ensure there’s plenty of flavor to balance the earthy lentils.
2Tbsp. virgin coconut oil
1small onion, chopped
2garlic cloves, finely chopped
11″ piece peeled ginger, finely chopped
1tsp. Diamond Crystal or ½ tsp. Morton kosher salt, plus more
¼cup Thai green curry paste
1medium sweet potato, peeled, cut into ½” cubes
¾cup brown or green lentils
4cups low-sodium chicken or vegetable broth
113.5-oz. can unsweetened coconut milk, shaken well
4cups (loosely packed) baby spinach leaves
½tsp. (or more) fish sauceSmall handful cilantro leaves with tender stems and lime wedges (for serving)
Heat oil in a large saucepan over medium. Add onion, garlic, and ginger; season with salt. Cook, stirring often, until onion is translucent and starts to soften, about 3 minutes. Add curry paste and cook, stirring and scraping bottom of pan constantly, until paste is fragrant and slightly darkened and mixture starts to stick to pan, about 3 minutes.
Stir sweet potato and lentils into onion mixture, then add broth and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt and bring to a boil. Reduce heat to a simmer and cook soup, stirring occasionally, until sweet potatoes are cooked through and lentils are tender but not mushy, 20–25 minutes.
Add coconut milk to soup; return to a simmer. Add spinach and fish sauce and cook just until spinach is wilted, about 30 seconds. Taste soup and season with more salt and/or fish sauce if needed.
Ladle soup into bowls and top with cilantro. Serve with lime wedges.