In a large mixing bowl, combine all-purpose flour, salt, and baking powder. Gradually add vegetable oil and warm water, mixing until a soft dough forms. Knead the dough on a lightly floured surface for about 5 minutes until smooth and elastic. Cover the dough with a damp cloth and let it rest for 30 minutes.

Heat a skillet over medium heat and add the ground beef or turkey. Cook, stirring frequently, until the meat is browned, about 7-10 minutes. Drain any excess fat and return the skillet to the heat. Add taco seasoning and a splash of water to the meat, stirring to combine. Cook for an additional 5 minutes, then remove from heat and let it cool.

Once the dough has rested, divide it into equal portions, about the size of a golf ball. On a floured surface, roll each portion into a 6-inch circle, approximately 1/8-inch thick.

On each circle of dough, place a spoonful of the prepared meat mixture in the center. Add a sprinkle of shredded cheddar cheese, diced tomatoes, chopped onions, and optional jalapeños or cilantro on top. Fold the dough over to create a half-moon shape, pressing the edges together to seal tightly.

In a deep pan or heavy skillet, add enough vegetable oil to cover the bottom and preheat it over medium-high heat to around 350°F (175°C).

Carefully place the sealed taco pockets in the hot oil, frying them for about 3-4 minutes on each side until golden brown and crispy.

Once golden, remove the taco pockets from the oil and drain on a plate lined with paper towels. Allow to cool slightly before serving with sour cream, guacamole, or salsa.