Prepare French Style Lentils according to on-pack preparation instructions and set aside.
Heat the oil in a large pot and add onion, bacon, carrot and garlic, cooking until onion is tender. Stir in the bayleaf and thyme, cooking for a further minute. Add stock, water, lentils and tomatoes. Bring to the boil, reduce heat and simmer for 30 minutes until lentils are tender. Remove bayleaf and thyme.
Add mint leaves to soup and using a stick blender, puree approximately half the soup, leaving some texture in the lentils. Return to the pot, stir in the lemon juice and season to taste. Serve soup with parsley and cheesy toasts.