Prepare the lentils: Rinse the red lentils thoroughly until the water runs clear.
Sauté the aromatics: In a large pot, heat a splash of broth, water, or oil. Add the onion, carrots, and garlic. Cook for about 5 minutes, stirring occasionally, or until softened.
Stir in the curry powder and cayenne. Cook for 1 minute to toast the spices.
Simmer the soup: Add the lentils and vegetable broth. Bring to a boil, then reduce the heat to low and simmer covered for about 15 minutes, or until the lentils are tender. Skim off any foam if needed. If you’d like a creamy version, blend the soup at this stage using an immersion blender before adding the greens.
Add greens & season: Stir in the chopped greens, cooking for 3 to 4 minutes until wilted. Season with salt and black pepper to taste.
Finish the soup: Remove from heat and stir in the lemon juice. Garnish with fresh dill or cilantro, if using, before serving.
