1 cup all-purpose flour, plus more for dusting
1 1/2 tablespoons granulated sugar
1/2 teaspoon unsweetened Dutch-process cocoa powder
1/4 teaspoon ground cinnamon
1/4 teaspoon coarse salt
3/8 cup sweet Marsala wine
1 1/2 tablespoons vegetable oil
1/2 large egg white, lightly beaten
2 ounces semisweet chocolate (preferably 61 percent cacao)
Confectioners' sugar, for dusting