In a large bowl, combine the flour and salt.
Add the vegetable oil and mix until the mixture resembles coarse crumbs.
Stir in the egg and gradually add cold water until the dough comes together.
Knead the dough on a floured surface until smooth.
Wrap in plastic wrap and let it rest for 30 minutes.
In a skillet, heat a small amount of vegetable oil over medium heat.
Add the chopped onion and cook until translucent.
Stir in the minced garlic and cook for another minute.
Add the ground beef or pork and cook until browned. Drain any excess fat.
Stir in the chopped green olives, grated cheese, tomato sauce, and chopped parsley.
Season with salt and black pepper to taste. Remove from heat and let it cool.
On a floured surface, roll out the dough to about 1/8-inch thickness.
Cut the dough into 4-inch squares or circles using a cookie cutter or knife.
Place a spoonful of filling in the center of each dough piece.
Fold the dough over the filling to form a triangle or half-moon shape. Press the edges to seal, using a fork to crimp the edges if desired.
Heat vegetable oil in a deep frying pan or pot over medium-high heat.
Fry the pastéis in batches, turning occasionally, until golden brown and crispy, about 2-3 minutes per side.
Remove with a slotted spoon and drain on paper towels.
Enjoy your meal!