Bundle the parsley stems, thyme sprigs and bay leaf in the slice of bacon and tie with kitchen string. Heat the olive oil in a medium saucepan. Add the onion and garlic and cook over low heat until softened, about 8 minutes. Add the carrot and celery and cook until softened, about 8 minutes. Add the cranberry beans, bacon bundle, stock, tomatoes and green beans and bring to a boil. Cover partially, reduce the heat to low and simmer for 10 minutes. Stir in the chopped parsley, lemon juice and lemon zest and season the soup with salt and pepper.