Chocolate Banana Empanadas

Name: Chocolate-Banana Empanadas
Ingredients: 4 large ripe bananas; 2 tablespoons sugar; 1 teaspoon cinnamon; 1 recipe empanada dough, recipe follows; 4 ounces semisweet chocolate, broken in chunks; Confectioners’ sugar, for dusting; 1 1/2 cups all-purpose flour; 1 cup masa harina; 1 teaspoon baking powder; 1 teaspoon salt; 1/2 cup (1 stick) unsalted butter, melted and cooled; 1 large egg beaten with 1 tablespoon water, for egg wash; Butter, for greasing the pans