How to Make It
In a medium bowl, whisk the sour cream with the buttermilk, thyme, cracked pepper and granulated garlic. Season with Tabasco and salt. Cover and refrigerate for at least 6 hours or overnight.
In a large skillet, heat the olive oil. Add the onion, celery, bell pepper, jalapeño and garlic and cook over moderate heat until the onion is translucent, about 5 minutes. Raise the heat to moderately high, add the pork and beef and cook until no trace of pink remains, about 5 minutes. Season with salt and freshly ground pepper. Transfer to a baking sheet and refrigerate until chilled, at least 20 minutes.
Arrange the empanada wrappers on a very lightly floured work surface. Spoon 2 tablespoons of the meat filling onto the lower half of each wrapper. Lightly moisten the edge of each wrapper with water, fold it over the filling and press the edges together to seal. Crimp decoratively with a fork.
In a large, deep skillet, heat 1 1/2 inches of oil to 375°. Line a baking sheet with paper towels. Working in batches, fry the meat pies, turning once, until golden, about 2 minutes. Transfer to the prepared baking sheet to drain, then serve hot with the black pepper dipping sauce.
Empanada wrappers, also called discos, are available in Latin American food stores and the freezer section of most supermarkets; Goya makes a good variety. If you can't find them, substitute wonton wrappers.