Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrots, and celery. Cook, stirring occasionally, for about 5 to 7 minutes until the vegetables have softened and the onion is translucent.
Stir in the minced garlic, ground cumin, smoked paprika, and dried thyme. Cook for about 1 minute until the spices are fragrant. This step helps to toast the spices and release their full flavor into the oil.
Add the rinsed lentils, diced tomatoes (with their juices), and the vegetable broth to the pot. Increase the heat to medium-high and bring the soup to a gentle boil. Once boiling, reduce the heat to low, cover the pot, and simmer for 25 to 30 minutes, or until the lentils are tender but not mushy.
Remove the lid and stir in the fresh spinach or kale. Let it sit for a minute or two until the greens have wilted. Stir in the lemon juice to brighten the flavors. Season with salt and black pepper to taste.
Ladle the hot soup into bowls and garnish with fresh parsley. If you prefer a thicker soup, you can blend a small portion of the soup and stir it back into the pot before serving.
Find it online: https://www.pleasecook.com/healthy/lentil-vegetable-soup/