In a medium saucepan over medium heat, add the water and butter, heating until butter has fully melted. Meanwhile, in a large bowl, whisk together flour, salt, and paprika and make a well in the center. Pour a little of the warm butter mixture in and mix with your fingertips to make a wet paste. Pour in remaining liquid, and work the dough with your hands until you get a wet, oily dough. Wrap the dough in plastic and refrigerate for at least 2 hours.

Heat 2 tablespoons of oil in a large skillet over medium heat. Saute the beef, cooking until browned, about 10 minutes. Remove the beef with a slotted spoon and set aside. Reserve 2 tablespoons of drippings.

After a few minutes, deglaze the pan with ¼ cup of beef broth, then add 1-2 tablespoons of tomato paste (to preference).

Once the tomato paste has dissolved, mix in the beef and potatoes. Remove from heat.

Tear off golf-ball sized pieces of the chilled dough and roll into balls. On a lightly floured work surface, use a rolling pin to roll out the balls into 1/4-inch thick, 5-inch diameter circles. Once your dough has been rolled out, place 2 heaping tablespoons of filling in the center of each dough circle. Add ½ teaspoon scallions to each circle, and sprinkle lightly with cheese, if using. Brush a small amount of egg wash lightly over one half edge’s border. Fold over the dough to create a half-moon shape and press edges firmly to seal. Crimp edges with the back of a fork.

Place empanadas onto the prepared baking sheet. Lightly beat together the egg and water. Brush the empanadas gently with the egg wash.

Bake empanadas until golden brown, about 20 minutes. Serve warm.

Refrigerate leftovers either plastic wrapped or stored in an airtight container for up to 3 days. You can also freeze cooked empanadas plastic wrapped in a resealable freezer bag or airtight container for up to 3 months. To reheat, unwrap as many empanadas as you want and warm through in a 300°F oven or toaster oven for about 10 minutes.