Place unwrapped dough on a lightly floured work surface.
Use rolling pin (I used a drinking glass), flatten dough slightly. Then start from middle and with gentle force, roll out starting from centr. Lift flattened dough and turn, ensuring that it doesn’t stick. Add a little more flour if needed. If dough cracks, just moisten with ice water and glue it back together. Roll out to about ¼ “ or ⅛ “ thickness, about 16” diameter.
Transfer dough to parchment-lined baking pan.
Brush centre surface with jam, leaving outer 3” margin.
Pour filling in centre.
Use palms of hands to pleat outer 3” crust over filling. Press lightly to maintain pleats, using a little water as glue. Lightly press on filling to fill in gaps. Add bits of butter over surface of fruit.
Ensure a few blueberries on top for appearance.
Brush milk on top crust surface. Sprinkle with a little sugar. If crust does not feel cold, place in fridge for 20 minutes before baking.
Bake for 15 minutes, then reduce oven to 350 degrees F and continue baking for about 30 minutes, or until crust is golden and fruit juices are bubbly.
Remove from oven and place on rack to cool slightly.Sift with icing sugar. Serve warm with vanilla ice cream. (Optional)