In a large saucepan with a lid, heat oil over medium-high. Add onion and cook, stirring, until softened and browned, 3 to 5 minutes. Add tomato paste, oregano, and thyme; stir to combine.
Add lentils, 5 cups water, and tomatoes with their juice; bring to a boil. Reduce heat and simmer, partially covered, 20 minutes. Add chard stalks and cook until beginning to soften, about 5 minutes. Add chard leaves; season with salt and pepper, and cook until lentils and chard are tender, 15 to 20 minutes.
Stir in lemon juice; ladle soup into bowls. Drizzle with olive oil, and serve with bread, if desired.
This is a tasty recipe! The soup took a while to prepare because the '15 minutes' that's quoted assumes you've already prepped all your veggies. It takes quite a while to clean and prepare the chard but it's worth the time! This recipe is very healthy, especially because the chard cooks in the broth which lets you consume ALL the nutrients. I had to add six cups of water (instead of five) to get enough broth, but the flavor was not compromised. Very good. Cheap, too!
This was the best lentil soup I have ever made. Very popular at a harvest potluck I made it for. Sooooo Good!