Step 1

Melt butter in a small pot or large saucepan over medium heat. When foam subsides, add onion, carrots, and celery and cook, stirring occasionally, until vegetables are beginning to soften but not developing any color, 8 to 10 minutes. Stir in garlic, ginger, thyme, spices, 2 teaspoons salt, and 1/4 teaspoon pepper; cook until fragrant, about 1 minute.

Step 2

Add tomatoes, lentils, and broth. Bring to a boil, then reduce heat to low, cover, and simmer until lentils are tender and creamy, 15 to 18 minutes. Remove and discard thyme. Transfer about one-third of soup to a blender; purée until smooth. (Be careful blending the hot liquid: Remove feed cap from blender lid and cover with a kitchen towel to let steam escape; or pulse several times with an immersion blender directly in pot to partially purée.) Stir purée back into pot, with coconut milk and lemon juice. Serve with any combination of serving suggestions.