Preheat the oven to 180 degrees Celsius.
In a small frying pan, dry roast the walnuts over a medium heat and set aside to cool. Once cooled, grind them in a food processor until the pieces are small but not powdery. Heat the oil in a frying pan and add the onions and garlic and cook for 2 - 3 minutes. Combine them in a bowl with the mushrooms, grated carrot, parsley, walnuts and breadcrumbs. Beat the eggs together with seasoning and combine thoroughly into the vegetable and nut mix.
Place the mixture into a loaf tin lined with kitchen paper and bake for 35 - 40 minutes. Serve warm with tomato and olive sauce and a green vegetable.
Note: Breadcrumbs are easily made (and guaranteed to be better for you) when you make them in a food processor using a quality wholegrain bread.