tough stalks removed and finely shredded
all-butter puff pastry 500g block
Fry the shallots in half of the butter until they are soft and browned: this will take about 15 minutes over a low heat. Tip into a bowl and add the walnuts, Stilton and thyme. Blanch the chard in boiling water for 1 minute, drain well and tip into the frying pan with the remaining butter and lots of seasoning. Cook for a minute or two to dry it out a little and then tip into the rest of the mix and cool.
Heat the oven to 200C/fan 180C/gas 6. Roll out the pack of puff pastry to the thickness of a £1 coin (about 35cm square) and cut into 2 pieces. Arrange the filling in a fat pile on one piece. Brush edges with beaten egg then drape the second piece over the top to make a parcel. Trim and crimp the edges. Score the top and decorate with pastry off-cuts, then brush all over with egg. Cook for 40 minutes, until crisp and golden.