1
Preheat the oven to 425°F. Line two baking sheets with parchment paper.
2
In a medium sauté pan, heat the oil over medium heat. Add the onion and sauté until tender, 4 to 5 minutes. Add the garlic and jalapeño, and sauté until fragrant, 1 minute more.
3
Add the ground beef and cook until well browned, 5 to 6 minutes. Add the taco seasoning and tomatoes, then bring to a simmer, mixing to combine. Season with salt and pepper. Transfer the mixture to a bowl and cool slightly.
4
On a lightly floured surface, roll out the dough to flatten any creases. Using a cookie cutter or the rim of a glass (about 3 inches in diameter), cut circles from the dough. You may need to flour the cookie cutter or glass between cuts. (Note: You can reroll the scraps of pie dough once to cut more circles.)
5
Place 1 tablespoons of filling in the center of a dough circle. Brush one side of the dough with water, then fold the dough over the filling, pressing gently to seal. Use the tines of a fork to fully seal the edge of the dough. Repeat with the remaining dough circles and filling. (The empanadas can be made up to this point and frozen in an airtight container. Thaw overnight in the fridge before moving on to step 6.)