Heat the oil in a large frying pan, add the
carrot, swede and onions, and cook for
8 mins. Add the garlic, rosemary, tomato
purée and yeast extract, and cook for a
further 5 mins. Add the tomatoes and
white wine and scrape all the goodness
off the bottom of the pan. Pour in the
stock, add the mushrooms and chestnuts,
then simmer for 8 mins until the sauce is
reduced and thickened. Remove from the
heat and allow to cool slightly.
Meanwhile, to make the topping,
put all the vegetables in a large pan of
salted water and bring to the boil. Cook
for 12 mins or until the vegetables are
tender. Drain, then allow to steam-dry
for 5 mins. Roughly mash the roots with
the butter, milk and some seasoning.
Heat oven to 190C/170C fan/gas 5. Pile
the mushroom mixture into an ovenproof
dish, top with the mash, then cook for
30 mins until golden and bubbling. Serve
with some buttered greens, if you like.