Using a small measuring spoon or melon baller, hollow out base and core of each pear, leaving a cavity for the filling.
Combine blue cheese, walnuts, sultanas and thyme and mix well. Fill the base of each pear with the cheese mixture.
Lightly dust a clean surface with flour and roll each pastry sheet until about one-third bigger. Cut two large rounds from each sheet and stand a pear on each.
Preheat oven to 190°C and line a baking tray with baking paper. Beat yolk, honey and water together to make an egg wash.
Gently fold pastry around pears, brush with egg wash and place on tray. Chill in fridge for at least 20 minutes before baking. Bake for 25-30 minutes or until pastry is golden and firm. Serve warm.