1 . Put the porcini mushrooms in a jug and pour 400ml of boiling water over them . Leave them to soak for 30 minutes , remove them , and remember to keep the liquid for later ! 2 . Dice the onion and carrot and crush your garlic . 3 . Heat some olive oil in a frying pan over a high heat . Add the king oysters with some salt - brown and soften them so that they can be shredded .

4 . Shred the mushrooms with 2 forks and set them aside until later .

5 . Heat more olive oil and then add the onion and carrot over a medium-low heat for 10 minutes until softened . 6 . Add the tomato puree , garlic and herbs . 7 . Pour the red wine into the pan , stirring it until it evaporates . 8 . Add the chopped tomatoes , porcini mushroom stock , porcini mushrooms , oyster mushrooms and marmite to the pan . Bring it to the boil , then turn the heat down - simmer for an hour . 9 . Cook your pasta . 10 . Add spaghetti to the ragù with some of the pasta water and you are done !