Cook pasta according to packet directions.
Heat olive oil to medium in a medium saucepan or Dutch oven. Sautee the onions and garlic for 5 minutes.
Add the carrot and mushroom then reduce heat to low and cook stirring occasionally for 10 minutes. Add the mushrooms, oregano, chilli flakes and paprika then fry for 2 minutes or until fragrant. Turn up heat to medium, add wine, bay leaves and tomato paste then bring to a boil. Simmer for 5 minutes.
Add the lentils and reduce heat to low. Cover and simmer for half an hour. Stir in the walnuts and vegetable stock then simmer for a further 15 minutes uncovered, season with salt and pepper. Toss the pasta through the sauce and serve.