Fry the onions in 50g of the butter in a
large pan. Add the sliced flat and chestnut
mushrooms, then soften for 5 mins. Stir in
the shiitake mushrooms and garlic, then turn
up the heat and cook quite fiercely to drive
off as much moisture as possible. Stir in
the Madeira, tarragon, breadcrumbs and
tomatoes, then take the pan off the heat.
In a separate pan, cook the button
mushrooms and pine nuts in the remaining
butter until the nuts are golden. Add to the
mushroom and tomato mixture, then cool.
Lay a sheet of filo on the work surface and
brush with oil. Top with another sheet, brush
again, then continue until you have a stack of
4 sheets of pastry. Spread half the filling down
the longest length, leaving several cms at
each end. Fold the pastry ends up over the
filling, roll up like a cigar, then carefully lift
onto a baking sheet. Brush with more oil,
then tear the last filo sheet into strips,
scrunch up and place half on top to decorate.
Repeat with the rest of the pastry and filling
to make a second strudel, then chill until
ready to cook. Can be made 1 day ahead.
To serve, bake in a preheated oven at
200C/fan 180C/gas 6 for 30 mins or until
golden and heated through. Serve in slices,
scattered with extra pine nuts and tarragon,
with the Madeira sauce.