For the Pastry:

1. In a large bowl, mix together the flour, sugar, salt, and baking powder.
2. Add the cubed cold butter and rub it into the flour mixture until you get a crumbly texture.
3. Beat the eggs with the cold water and add to the flour mixture. Mix until the dough comes together.
4. Cover the dough and let it rest in the fridge for 30 minutes.

For the Filling:

1. Heat the oil in a large pan over medium heat. Add the chopped onions and sauté for 5-6 minutes until soft.
2. Add the diced carrots and potatoes, cooking for an additional 3-4 minutes.
3. Add the ground beef to the pan, breaking it apart as it cooks, for about 4-5 minutes.
4. Season the mixture with salt, pepper, thyme, and flour, then add the water or beef broth. Let it simmer until the filling thickens, around 5 minutes. Set aside to cool.

Assembly:

1. Divide the dough into 4 equal pieces and roll each piece into about 1/8-inch thickness.
2. Use a round cutter (or a bowl) to cut out circles from the dough, making them as large as you prefer for your pies.
3. Place 1-2 tablespoons of the meat mixture in the center of each dough round.
4. Fold the dough over to form a half-moon shape and seal the edges with your fingers or a fork.
5. Poke a few holes in the top of each pie to allow steam to escape while baking.

Baking:

1. Preheat the oven to 375°F (190°C).
2. Place the pies on a baking sheet and brush the tops with a beaten egg for a golden finish.
3. Bake for 25-30 minutes until the pies are golden brown and crispy.
4. Let the pies cool slightly before serving.