Nigerian Meat Pies

For the Beef Filling: In a small bowl, whisk cornstarch with 1/2 cup (120ml) water until well combined and set aside. Serious Eats / Maureen Celestine In a 10-inch cast iron or stainless-steel skillet, heat 1 tablespoon oil over medium heat until shimmering. Add ground beef, season lightly with salt, and cook, stirring and breaking up chunks of meat, until beef is no longer pink, about 5 minutes. Transfer to medium heatproof bowl and set aside. Serious Eats / Maureen Celestine Add remaining oil to now-empty skillet and continue to heat on medium until shimmering. Add onion, potatoes, and carrot, season with salt, and cook, stirring occasionally, until just beginning to soften, about 4 minutes. Add curry powder and thyme and cook, stirring frequently, until fragrant, about 2 minutes. Serious Eats / Maureen Celestine Add cooked beef along with the stock or water, cover, and bring to a boil. Reduce heat to maintain a simmer and cook, stirring once or twice, until vegetables are softened, 12 to 15 minutes. Serious Eats / Maureen Celestine Stir in half of the green bell pepper and cook until just softened, about 2 minutes. Stir cornstarch slurry to redistribute the starch, then stir into the beef mixture. Bring to a simmer and cook, stirring occasionally, until beef and vegetables are coated in a thickened sauce, about 5 minutes. Stir in remaining green bell pepper and season with salt and pepper to taste. Transfer to medium heatproof bowl and set aside to cool, about 30 minutes (filling can be refrigerated in an airtight container for up to 3 days). Serious Eats / Maureen Celestine For the Dough: Meanwhile, in a large bowl, whisk together all-purpose flour, whole wheat flour, salt, and baking powder until thoroughly combined. Serious Eats / Maureen Celestine Using the large holes of a box grater, grate butter over flour mixture. Using your hands, toss grated butter with flour mixture until butter is evenly distributed. Serious Eats / Maureen Celestine Make a 4-inch wide well in the center of the butter-flour mixture. Whisk beaten egg and ice-cold water together until combined. Pour egg mixture into well, then, using a flexible spatula, gradually stir butter-flour mixture into egg mixture until a cohesive dough forms with visible bits of butter. If dough is too dry, add additional water, 1 tablespoon at a time, until dough comes together. Shape dough into a flat, round disk, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes or up to 2 days. Serious Eats / Maureen Celestine Set dough disk on a generously floured work surface. Portion into 6 equal-sized balls (2 1/3 ounces; 65g each). Using a rolling pin and adding more flour as needed underneath and on top of dough to prevent sticking, roll out each ball into a 6-inch circle about 1/8 inch thick. Transfer rounds to a lightly-floured rimmed baking sheet and cover loosely with plastic wrap to prevent dough rounds from drying out. Serious Eats / Maureen Celestine To Assemble and Bake: Line a rimmed baking sheet with parchment paper. Working with one dough round at a time, set on a lightly-floured work surface and add 1/2 cup (3 1/2 ounces; 98g) of beef filling to bottom half of the round, leaving a 1/2-inch border along the edge. Fold top half over the filling to form a semicircle, then press down gently around the edge to seal. Using the back tines of a fork, press down firmly around the edge to ensure meat pie is well sealed. Transfer to a prepared baking sheet and cover loosely with plastic wrap. Repeat the process with remaining dough rounds and filling. Cover loosely and refrigerate at least 30 minutes and up to 2 hours. Serious Eats / Maureen Celestine Twenty minutes before baking, adjust oven rack to middle position and preheat to 400°F (205°C). When ready to bake, brush surface of pies with egg wash. Poke pies all over with a fork, 5 to 6 times each. Bake meat pies, rotating tray halfway through, until golden brown on all sides, about 25 minutes. Let cool for 10 minutes. Serious Eats / Maureen Celestine Transfer meat pies to a serving platter and serve warm or at room temperature. Serious Eats / Maureen Celestine