Begin by making the filling. Preheat the oven to 350 degrees F (175 degrees C). Place the beef in a roasting pan and season with bay leaves, salt and pepper. Roast for 1 hour or until tender.
While the meat is cooking, heat the oil in a large skillet over medium-high heat. Add the onion, pepper, garlic, and shallots and cook for about 3 minutes until softened. Add the scallion, paprika, sazon completa, oregano and cumin; season with salt and pepper to taste. Add the roasted beef to the skillet along with any accumulated juices from the roasting pan. Cook for a few minutes to combine flavors. Remove from heat and set aside to cool.
To make the dough, place the sugar, oil, butter, salt, cornmeal and flour in a food processor and pulse until a smooth dough is formed. Grease a baking sheet with oil or butter. Roll out the dough on the greased baking sheet into an 11-inch diameter circle about 1/4-inch thick. Cut into 12 wedges using a sharp knife or pizza cutter.
Place 2-3 tablespoons of filling onto each wedge, leaving about 1/2 inch around the edges for sealing. Fold over each wedge to form an empanada shape (it should look like a half moon). Seal edges by pressing with a fork or your fingers.
Heat oil in a large skillet over medium-high heat. Fry the empanadas for 2 minutes on each side or until golden brown and cooked through. Serve with your favourite salsa or dipping sauce, if desired.
To make the sauce, combine all ingredients in a food processor and process until smooth. Taste and adjust seasonings to your preference. Serve with the empanadas as desired.