In a large mixing bowl, whisk together the all-purpose flour and salt until evenly distributed.

Pour the melted butter, egg yolks, and water into the flour mixture.

Using clean hands, mix the wet and dry ingredients together until a shaggy dough begins to form. Transfer to a lightly floured surface and knead until a smooth, consistent ball develops. If the dough feels sticky, gradually add flour one tablespoon at a time.

Wrap the dough in plastic wrap or cover with a clean kitchen towel. Refrigerate for at least 30 minutes to allow the gluten to relax.

Remove dough from refrigerator and divide into 16 equal portions. Roll each portion into a ball, then use a rolling pin to flatten each ball into a 5-6 inch circle, about 1/8 inch thick.

Place 2-3 tablespoons of desired filling in the center of each circle. Lightly brush the edges with water, fold the dough over to create a half-moon shape, and seal the edges using a fork or by crimping with your fingers.

For baked empanadas: Brush with egg wash and bake at 400°F for 20-30 minutes until golden brown. For fried empanadas: Heat oil to 350°F and fry each side until golden brown and crispy.