Place the flour, sugar, salt and cold butter in a bowl and quickly blend with your fingers to break the butter into small pea-size pieces (this can be done in a food processor as well). Slowly add some cold water and blend until you have a dough that just holds together when squeezed. Wrap the dough in plastic wrap to form a flat disc and chill for at least 25 minutes.
In a heavy bottomed pot add the blueberries, star anise, sugar and cornstarch with a splash of water. Cook over medium low for about 20 minutes, stirring occasionally until the blueberries have broken down and the juices have thickened. Set aside to cool.
Roll the chilled dough out into a rectangle and cut into four equal smaller rectangles.
Place a heaped tablespoon of the blueberry filling onto one end of the rectangle. Fold the tops over the bottom and press the sides closed. Use a fork to further pinch the edges together.
Brush each pie with egg wash and sprinkle with sugar. Cut a small “x” in the top to vent.
Bake at 375 for 25 - 30 minutes until just golden brown.
