1 1/3 cup (about 8 ounces) red lentils, picked through and rinsed
7 cups low-sodium vegetable broth
1 large onion, diced
1 large carrot, diced
4 cloves garlic, finely chopped
2 tablespoons tomato paste
1 teaspoon ground cumin
1/8 teaspoon cayenne pepper, or to taste
3/4 teaspoon fine sea salt, or to taste
Lemon wedges and chopped mint for serving (optional)
In a large pot, combine lentils, broth, onion, carrot, garlic, tomato paste, cumin and cayenne and bring to a boil over high heat. Lower heat and simmer, uncovered, until vegetables and very tender and lentils begin to fall apart, about 25 minutes.
Remove the pot from the heat and use an immersion blender to quickly blend the soup until it is creamy but not completely puréed. Or, you can blend about half the soup in a blender, but use caution when blending hot liquids: blend only in small batches, hold the lid down firmly with a kitchen towel, and begin blending on low speed. Add salt and serve with lemon wedges and a garnish of mint if desired.