
In a heavy bottomed pot, add olive oil and set over medium heat. Add the onions, carrots, and celery and cook for 10 minutes until softened.
Add garlic, cumin, paprika, and thyme, salt, and pepper, and cook until the garlic is fragrant, about 1 minute.
Add the lentils, potatoes, tomatoes, and vegetable broth and bring to a boil. Reduce heat to a simmer and cook for 30-35 minutes, stirring occasionally.
Once the lentils are tender, use an immersion blender to blend part of the stew for a thicker consistency. Alternatively, you could transfer 2 cups of stew to a high speed blender and blend until creamy.
Return the blended soup back to the pot with spinach and cook for another 2-3 minutes until the spinach is wilted.