A hearty, earthy Greek lentil soup — adapted with Japanese sweet potato, butter, and umami seasoning. The definitive version, dialed in after the first cook.
Heat the olive oil and butter in a large pot over medium heat. Add the onion and sweet potato and cook, stirring occasionally, until the onion is softened and the sweet potato picks up a little color, about 5–6 minutes. Add the garlic and cook 1 minute more until fragrant.
Stir in the cumin, smoked paprika, and oregano. Cook for about 30 seconds, stirring constantly, until the spices bloom and become aromatic. This deepens the flavor significantly.
Add the crushed tomatoes, bay leaves, and water. Season generously with salt, pepper, and umami seasoning. Bring to a boil, then reduce heat and simmer partially covered until the sweet potato is fully tender.
◴ 15–20 minutesStir in the pre-steamed lentils and simmer for 5 minutes to let them warm through and absorb the broth flavors. Add a splash more water if it's thicker than you'd like.
◴ 5 minutesRemove the bay leaves. Stir in the balsamic vinegar — start with 1 tablespoon, then taste. The soup should taste bright but not sweet. Adjust salt, pepper, umami seasoning, and vinegar. Ladle into bowls and finish with a generous drizzle of good olive oil.
With pre-cooked lentils this comes together fast. The key is simmering the sweet potato until tender before adding the lentils — they only need a few minutes to warm through and soak up the broth. Don't be shy with the lentils — this version is hearty.
The butter and umami seasoning aren't traditional, but they push this into a different league. Balsamic is sweeter than the traditional red wine vinegar, so start with 1 tablespoon and taste. A generous drizzle of good olive oil at the end is essential. Season boldly — this soup rewards it.
Leftovers thicken considerably overnight. Just thin with a splash of water when reheating.