Just about every culture has a variation of a meat pie. For example, Jamaican Beef Patties, Cornish Pasties, Chinese Pork Buns, Mediterranean Pide (Pita), and in the US Pot Pie. Even within a region or country the ingredients vary widely. This recipe is one version that my husband likes.
Measure the masarepa into a large bowl, add the sazon, if using, and salt, and mix well. Add water and mix to form a dough (it will be a bit wet and rubbery). Let stand while preparing the filling.
Meanwhile, cook the potatoes with water and the bouillon until tender, about 10 minutes. Drain, mash lightly, and set aside.
In a large, heavy skillet, heat 1 tablespoon oil; add onion, tomatoes, green onions, garlic, bell pepper, and cilantro. Cook, stirring occasionally, until tomatoes break down, about 15 minutes. Add ground beef, season with salt, pepper, cumin, and sazon. Cook, breaking up the beef with a wooden spoon, until browned and fairly dry.
Stir in the potatoes and mix well.
Heat at least 2-inches of oil over medium high heat.
Break off a golf ball sized section of the dough (1.5 ounces) and with your hands, roll it into a ball. Place between plastic wrap and flatten, with the heel of your palm, into a 6-inch disc. Peel away the plastic from the top only and scoop the bottom plastic and the disc into your palm. Place a heaping tablespoon of the filling in the center, then fold the disc and pinch the ends closed. Slighly flatten to distribute filling. Do the same with the remaining dough and filling.
With a slotted spoon, gently lower the empanada into the hot oil and cook 2 minutes, turning about halfway through. Drain on paper toweling. You'll need to cook these in batches.
Serve warm or at room temperature with Aji or Avocado Sauce, and/or lime wedges.