Put blade attachment on food processor. Add flour, salt and cold butter chunks. Pulse several times until butter is reduced to the size of peas, then add egg and cold water. Pulse again, continuing only until mixture comes together in a cohesive ball of dough. Remove dough; shape it with your hands into a flat round circle. Wrap tightly in plastic wrap; refrigerate dough one hour (at least!).

Heat olive oil on medium in a large skillet. Once hot, add red onion, jalapeños and green chiles. Sauté until they've softened slightly (2-3 minutes). Stir in salt, chili powder, paprika and cumin. Add tomato paste; stir until combined. Sauté 2 more minutes. Add ground beef. Cook until meat is browned/fully cooked, breaking up the meat as it cooks (about 4-5 minutes). When done, take skillet off the heat; let the filling cool slightly (3-4 minutes). Stir in cooked diced potato, frozen peas, green onion and parsley until combined.

Unwrap cold pastry dough; put dough on floured work surface. Roll dough out until it is about ¼" thick. Use a biscuit cutter, small bowl or ring cutter that is approx. 5" in diameter. Cut dough into 12 circles, approximately 5" in diameter. Gather/re-roll leftover dough; cut additional circles until you have 12 total. Roll dough circles out just a little bit more to make them slightly larger.

Spoon about ¼ cup of the filling in the center of each dough round. Avoid overfilling or it will be harder to fully enclose and seal in the filling. Fold empanadas in half by bringing one half of the dough up and over the filling until it reaches the other edge (half-moon shape). Pinch edges together to seal, then carefully crimp edges with the tines of a fork to tightly seal filling inside. Make sure empanadas are fully sealed to prevent filling from leaking out while cooking. 

Fill an electric skillet OR a large skillet or large saucepan with vegetable oil until oil reaches 1" in depth. Heat oil until it registers between 360°-375°F. on a digital thermometer. Do NOT add empanadas to the oil until it has reached the correct temp. (for best results). Once oil is at temp, add 2-3 empanadas to the oil at a time. Fry for 2-3 minutes, then turn them over; cook the other side 2-3 minutes. When done, both sides should be lightly browned and crispy. Transfer them from the oil onto a wire rack (over paper towels to absorb any oil drips). IMPORTANT: After cooking a batch, it is really important to let oil re-heat to the correct temperature again before frying the next batch!

Let empanadas cool slightly before serving. Serve with favorite condiments (guacamole/sour cream/salsa, etc.). Enjoy!