Prepare the Pastry: In a large bowl, combine flour and salt. Cut in the butter until the mixture resembles coarse crumbs. Slowly add cold water, mixing until dough comes together. Form into a ball, wrap in plastic, and refrigerate for at least 30 minutes.
Cook the Filling: Heat vegetable oil in a skillet over medium heat. Add onion and garlic, cooking until softened and fragrant. Stir in ground beef and cook until browned. Mix in tomato paste and cook for 2 more minutes. Remove from heat and let cool slightly.
Assemble the Pies: Preheat oven to 375°F (190°C). Roll out pastry on a floured surface to about 1/8-inch thick. Cut circles (about 5–6 inches wide). Place a spoonful of beef filling in the center of each circle. Fold over and crimp the edges with a fork to seal.
Bake: Place pies on a lined baking sheet. Brush tops with a little beaten egg or milk for a golden finish. Bake for 25–30 minutes, or until the pastry is puffed and golden brown.
