Combine 1½ cups blueberries in a saucepan with ¼ cup sugar, and the lemon juice and zest. Bring to a boil, reduce heat and simmer for 5 minutes or until the blueberries are very soft and start to burst. Combine the corn starch with 2 tablespoons water and stir into the blueberries, increase heat, bring back to a boil, and boil until the mixture thickens, about 30 seconds. Add the remaining ½ cup blueberries and let cool completely. (To speed up the cooling process place the sauce pan in a large bowl of ice water for a few minutes and stir occasionally until cool.)
Preheat oven to 400 degrees. Line a baking sheet with parchment paper or a silicon baking mat.
Combine the bread mix with 2 eggs, the oil or melted butter, and ¼ cup of water. Stir until just combined. Dump the mixture out onto a clean work surface and knead until smooth, about 1 minute. Divide the dough into 6 equal portions and roll into balls. Place a piece of wax or parchment paper on your work surface, place a piece of dough on top, top with another piece of paper, flatten into a disk and roll into a 6 inch circle. Spread 2 heaping tablespoons of the cooled blueberry mixture on one half of the dough leaving a ½ inch border at the edge. Fold the dough over forming a half circle. Pinch the dough edges together, fold over to crimp, and place on the prepared baking sheet. Repeat with the remaining dough and blueberries.
Using a fork, pierce the top of the dough several times. Whisk the remaining egg with a splash of water, brush on the top of the hand pies, and sprinkle with sugar. Bake for 20 minutes or until the crusts are lightly browned. Let cool.