In a large pot over medium heat, warm 2 tablespoons of olive oil. Add the diced onion, chopped celery, and carrots, cooking until softened and slightly translucent, about 3–4 minutes. Toss in the minced garlic and sauté for an additional minute until fragrant.

Pour in 6 cups of vegetable broth, then add 1 cup of red lentils, 2 bay leaves, 1 teaspoon of turmeric, and 1 teaspoon of cumin. Bring the mixture to a hearty boil, then reduce the heat to low. Cover the pot and simmer for 12–15 minutes, stirring occasionally.

Remove the pot from heat, then stir in the juice and zest of 1 lemon, along with salt and pepper to taste. Blend 2 cups of the soup using a blender or immersion blender, then stir the blended mixture back into the pot.

If you’re adding greens, stir in a couple of handfuls of spinach or kale until wilted, about 2–3 minutes. Taste for seasoning and serve hot.