Grease the baking sheet with butter.
To make the filling place the butter in the small saucepan and heat until melted and starting to foam.
Add the remaining filling ingredients and stir in. Remove from the heat and allow to cool.
To make the pastry sift the flour and salt into the large mixing bowl.
Cut the butter into very small chunks and add them to the bowl and stir them in.
Add the cold water and bring together to a loose dough with a lumpy consistency.
Cover with clingfilm and place in the fridge for 30 minutes.
Place the dough on a floured work surface and shape into a rectangular block.
Roll the dough to a rectangle three times longer than it is short, keeping the edges straight and even.
The rolled-out pastry should have a marbled effect from the lumps of butter.
Fold the top third down to the centre, then the bottom third up and over that.
Give it a quarter turn and roll out again to the original sized rectangle.
Repeat the folding, turning and rolling out 3 more times or until the marbling effect has disappeared. Fold once more and place in the fridge for 30 minutes.
Preheat the oven to 170C/325F/gas 3.
Place the chilled dough onto a lightly floured surface and roll out to 16 x 24cm and about 2mm thick.
Cut 20 triangles (8cm each side).
Lay 10 triangles out and place a tablespoon of filling in each centre. Brush the edges lightly with beaten egg.
Working one at a time, place an unfilled triangle on top of a filled one and press down securely with your fingers. Pinch the edges and tuck under the godcake and place on the prepared baking sheet.
Make three slashes across the top of each cake, brush with the egg white and dust with caster sugar.
Place in the preheated oven and bake for 20-25 minutes or until golden.
Remove from the oven and allow to cool on the baking sheet. Serve warm or at room temperature.
