• Mix the flour, salt, sugar (if using), and baking powder in a food processor.
• Add the pieces of butter and pulse until mixed.
• Add the orange juice and sparkling water – start with ½ cup of water and then add more as needed, pulse and mix until clumps of dough start to form.
• Form a ball with the dough and knead lightly.
• Place the dough in bowl, coat with small amount of oil, cover and let rest at room temperature for about an hour.
• To make the empanada discs or rounds, you can either roll out the dough into a thin layer and cut out round disc shapes for empanadas (use round molds or a small plate). Or you can make several small balls of dough, about 1.5 oz to 2 oz in weight, then use a tortilla press or a rolling pin to roll them out – they don’t need to be perfectly round. It's really important to get the discs very thin since they cook very quickly when you fry them, if after cutting out the round shapes or pressing them with a tortilla press, they are still thick, try rolling each disc a little more until it is very thin. Some people also use a pasta machine to get the dough very thin.
• The empanada discs can be used immediately or stored in the refrigerator or freezer to use later.

To fill, assemble, and fry the empanadas:

• Use a spoon to place your choice of filling on to the center of each empanada disc.
• Fold the empanada discs and seal the edges, first pressing gently with your fingers, then use your fingers to gently twist the edges of the empanada. You can also use a fork to press down and seal, or one of those empanada molds if you have one.
• If you have time, I recommend chilling the empanadas for 30 minutes to an hour (or longer if you are making them ahead of time), before frying them.
• The empanadas can be fried either a deep fryer or a simple frying pan, just make sure to have enough oil to cover at least half the empanada if using a pan. Heat the oil, it should bubble when you add the empanadas to the oil, and fry each empanada until they are golden on each side. Don’t overcrowd the pan and if any of them break/leak remove it immediately from the oil.
• Place the fried empanadas on paper towels to drain any extra oil.
• Serve warm.