Sweat the vegetables. Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrots, and celery with a pinch of salt. Cook, stirring occasionally, for 7 to 8 minutes until softened and the onion is translucent. This slow start builds the sweet, savory foundation of the soup.

Bloom the spices. Add the garlic, cumin, smoked paprika, turmeric, and thyme. Stir constantly for 1 minute until intensely fragrant. Toasting spices in oil wakes up their flavor in a way that just dumping them into liquid never does.

Add lentils and liquids. Stir in the rinsed red lentils, diced tomatoes with their juices, and vegetable broth. Add the salt and pepper. Bring to a boil, then reduce to a gentle simmer.

Simmer until creamy. Cook uncovered for 20 to 25 minutes, stirring occasionally, until the lentils have broken down and the soup is thick and creamy. Red lentils dissolve as they cook, which is exactly what you want. If the soup gets thicker than you like, stir in a splash of water or broth.

Wilt the greens. Stir in the kale or spinach and cook 3 to 5 minutes more, until wilted and tender. Kale needs the full 5 minutes; baby spinach wilts in about 2.

Finish with lemon. Remove from the heat and stir in the fresh lemon juice. Taste and adjust salt, pepper, and lemon. This final seasoning is what makes the whole pot come alive, so do not skip the tasting step. Serve hot with a drizzle of olive oil and fresh parsley.