In a large soup pot or dutch oven, heat the olive oil.
Add the red pepper, onion, carrot, and celery to the pot.
Cook until onion is translucent (about 6 minutes).
Stir in the minced garlic, oregano, bay leaf, basil, salt, & pepper and cook until fragrant (about 3 minutes).
Add the can of tomatoes, dried lentils, broth, and water.
Bring to a boil, reduce heat, and simmer for 1.5 hours or until the lentils are soft.
Optional add broth to get the desired consistency for your soup.
Right before serving add in the spinach and lemon juice.
Add additional salt & pepper to taste.