Dry-roast the nuts in a medium-hot oven for 15 minutes, then rub off the skins and finely chop with the sugar. Add the orange-flower water, then set the mixture aside.
Take 2 filo pastry sheets, overlap slightly on the long sides, and stick them together with egg white. Butter generously, then fold in the top and bottom edges to form a rectangle. Place a quarter of the filling in the centre, fold the pastry sheet over into the centre then again to bring in the sides, flattening slightly to make a parcel around 5 cm (2 inches) wide. Repeat to make a total of four long parcels. Place on a tray, cover with clingfilm and place a weight on top. Leave overnight.
Preheat the oven to 150°C (300°F), Gas Mark 2.
Unwrap the cakes and place them in a buttered baking tin. Slice each cake into six pieces on the diagonal, using a very sharp knife. Do not separate them completely. Transfer the tin to the oven and cook for 20 minutes.
Meanwhile, heat the honey with the orange-flower water for the glaze. Immediately the baklavas are cooked, coat them with the hot glaze. Leave to stand for 1 hour before removing them from the tin.