Add the mushrooms, walnuts, onion, carrot, and garlic to a food processor and pulse until textured
Heat a pan with oil and add the mushroom mixture along with the dried herbs and fry for a few minutes
Add the chopped tomatoes, peas, yeast extract/marmite, salt and pepper and simmer with the lid on for 10-15 minutes
Peel and chop the potatoes and boil for 10 minutes until soft
Drain the potatoes, add the butter, milk, salt and pepper and mash until smooth
Transfer the mushroom mixture into a large baking dish, top with the mash and press it down
Drizzle over a little oil and bake at 200°C for 30 minutes
