In a food processor, blend together flour, cornstarch, sugar and salt. Pulse to combine ingredients until thoroughly distributed. 

Add egg to processor and pulse until combined, about 5-6 times

Add 12 tbsp of cold butter, cut into chunks, to food processor. Pulse until mixture begins to take on a sandy texture and butter is distributed. 

Slowly add ice cold water, one tablespoon at a time, until a dough starts to form. Linda usually does only one tablespoon. I needed two. 

Remove dough from food processor and place onto a piece of parchment paper, sprinkled with a bit of flour. Knead dough until smooth and pliable. The heat from your hands will melt any bits of butter in the dough. (At this point the dough can be refrigerated to use later if needed.) 

Divide dough in half. Lightly dust your surface again with flour, and roll the first half of dough. Use a circle cookie cutter to cut your rounds for your hand pies. You should get 12-13 per dough half. Store in the fridge, and repeat with remaining half of dough. (Super cold dough helps in the baking process.) 

Once all circles have been cut and chilled, remove from refrigerator and prepare to fill the hand pies. In a small dish, whisk together one egg and one tbsp water to create an egg wash. 

Place half of the cut circles on a parchment lined baking sheet and brush with egg wash. These will be the bottoms of your hand pies. 

Next, place one tablespoon of filling on each bottom. 

Cover each topped circle with another circle of dough. Use your finger to press down around the other egg, sealing the dough circles together. Repeat until all bottoms have tops. 

Brush the tops of the sealed hand pies with egg wash, and sprinkle with sugar. Use a toothpick to pierce two or three holes in the top of each hand pie. This allows steam to escape and prevents the seams from splitting. 

Return hand pies to fridge while preheating oven to 350 degrees.

Once the oven is heated, bake hand pies for 25-30 minutes. I find it best to rotate the pan 180* halfway through cooking.  

Once finished baking, allow to cool to room temperature. You can add a simple glaze if you like, but I find these to be delicious on their own.