In a large bowl, combine flour, salt, and baking powder. Whisk together until well mixed.

Incorporate the chilled, cubed butter into the flour mixture using a fork or pastry cutter. Mix until the mixture resembles coarse crumbs.

In a separate bowl, whisk together the egg and cold water. Gradually add this mixture to the flour mixture, stirring until combined.

Turn the dough onto a lightly floured surface and knead it gently until smooth. Wrap in plastic wrap and refrigerate for 30 minutes to 1 hour.

In a skillet over medium heat, cook the ground beef (or alternative protein) until browned. Drain excess fat if necessary.

Stir in the taco seasoning and any optional diced onions and peppers. Mix well and cook for an additional 5 minutes until everything is heated through. Remove from the heat and allow to cool slightly.

Mix in the shredded cheese until well combined.

Preheat your oven to 400°F (200°C). Prepare a baking sheet by lining it with parchment paper and lightly spraying or oiling it.

On a floured surface, roll out the chilled dough to about 1/8 inch thick.

Use a ghost-shaped cookie cutter to cut out shapes from the dough. Re-roll scraps as needed to make more ghost shapes.

On half of the ghost shapes, place about a tablespoon of the filling mixture, being careful not to overfill.

Take the other half of the ghost shapes and place them on top of the filled ones. Press the edges together firmly and use a fork to crimp the edges for a more secure seal.

Brush the tops of the hand pies with the egg wash to give them a golden brown finish.

Place the assembled hand pies on the prepared baking sheet and bake for 20-25 minutes, or until they are lightly golden brown.

Let the hand pies cool slightly on a wire rack before serving. These are best enjoyed warm but can also be stored in the refrigerator and reheated later.