Melt butter in a small saucepan over low heat and stir in filling ingredients.
Preheat oven to 220°C and grease a baking tray with margarine.
Roll out pastry on a floured surface to 3mm thickness.
Cut pastry into 6cm rounds and place a teaspoon of filling in the center of each.
Brush edges with milk, fold over, and pinch corners to seal.
Flip parcels seam-side down and roll out to 0.5cm thickness.
Slash each cake three times, brush with milk, and sprinkle with caster sugar.
Bake for 15 minutes until golden-brown and puffed.
Cool on a wire rack and dust with icing sugar before serving.