Boil or steam the parsnips. Preheat oven to Gas Mark 4 / 180 °C / 350°F.
Heat 1 tbsp. olive oil in a pan and fry the onions and garlic.
Place them in a bowl with the ground cashew nuts, herbs and corn flour.
Mash the boiled parsnips and add them to the bowl.
Dissolve the yeast extract in the stock and add to the bowl.
Fry the mushrooms in 1 tbsp. oil until soft.
Grease a 2 lb loaf tin (I’m not sure what the metric equivalent of a 2 lb loaf tin is. It’s a bread tin about 20 cm long, 10 cm wide and 8 cm deep).
Press half the nut mixture into the tin, cover with the mushrooms and top with the rest of the mixture.
Wrap the loaf tin in foil and bake for 1 hour.
Remove from oven and allow to stand for 10 minutes before serving.