Spinach and Lentil Soup with Cheese and Basil

This recipe can be prepared in advance — just wait for the spinach to stir while you reheat the soup.
Preheat a roasting pan over medium-high heat. Pour the oil into the pan; stir to coat. Add the pancetta; cook for 1 minute or until the pancetta begins to brown, stirring occasionally. Add the onion and the next 4 ingredients (via the bay leaf); cook for 8 minutes or until the vegetables are tender, stirring occasionally. Add the lentils, stock, and 2 cups of water; bring to a boil. Cover, reduce the heat, and simmer for 40 minutes or until the lentils are soft and the mixture thickens slightly. Remove from heat. Discard the bay leaf.Combine 2 cups of the lentil mixture in a blender. Remove the center part of the blender lid (to release steam) and secure the blender lid to the blender. Cover the hole in the blender lid with a clean towel (to avoid splashing) and beat until smooth. Add the mashed lentil mixture to the skillet. Add the spinach, chopped basil, parmesan cheese, lemon juice, and black pepper; stir until the spinach wilts. Serve immediately.