For Hand Pie Crust:

1. Add the flour and salt to the bowl of a food processor. Add in the butter and pulse 5 times.
2. Add the vinegar to the water. With the motor running, slowly pour in half the water / vinegar into the flour. The dough should be crumbly and it should hold together when squeezed. Drip in more water and toss together as needed.
3. Empty the flour mixture onto a work surface and divide into two piles.
4. Quickly using your hands form each dough pile together. If there are any dry spots drip a bit more water on them and knead together if you have to. Place each in a piece of plastic wrap and wrap tightly. 
5. Using a rolling pin, roll the dough out until it stretches to the corner of the plastic wrap. 
6. Refrigerate for at least 4 hours, but preferably overnight

Make Supreme Pizza Filling:

1. Heat olive oil in a large pot over medium heat. Add sausage, and cook until no pink remains, about 5 minutes.
2. Add in onion, pepper and garlic and cook until softened, about 5 minutes.
3. Add in pizza sauce, pepperoni, italian seasoning and garlic powder. Cook until bubbling, about 2-3 more minutes.
4. Shut off heat. Let cool slightly, then taste and adjust seasoning, adding salt and pepper as needed.
5. Let cool completely, and then mix in the mozzarella. Set aside in the refrigerator until ready to use.

Roll Out Dough:

1. Remove the chilled dough from the refrigerator and let rest at room temperature for 5-10 minutes, or until the dough is slightly softened, so it is easier to roll.
2. On a well-floured work surface, roll out one piece of dough to a rough rectangle, about 1/8” thick. Using a pastry wheel or a knife, cut out 3 x 4-inch rectangles. Repeat with remaining dough. Then gather up the scraps and roll out the dough in the same manner, cutting out as many rectangles as possible. This dough should yield about 24 rectangles.
3. Line two baking sheets with parchment paper and place 6 rectangles down on each of the baking trays.
4. Place roughly 3 tablespoons or so of filling in the middle of a rectangle. Place one pastry rectangle on top, taking care to seal the edges. Take a fork and crimp the edges. Using a pastry bench scraper, press down to cut off the edges of the pastry. This makes the final product look neat, but it also seals the hand pies well. If you are having trouble successfully closing them up, adjust the amount of filling. Repeat with the remaining rectangles for both baking sheets. 
5. Chill the tray of hand pies in the refrigerator for at least 30 minutes. Once chilled, using a knife, gently cut holes through the top of the dough to let the steam escape during baking.

Bake:

1. Preheat the oven to 400 degrees and place a rack on the lowest rack and the middle rack.
2. Make an egg wash, and brush on top of the hand pies. Sprinkle the tops with italian seasoning and parmesan cheese. 
3. Bake the hand pies in the oven for 25-35 minutes, switching the trays halfway through, until the pastry is a deep golden color.
4. Let the pies cool slightly before serving. Serve with pizza sauce, for dipping, if desired.