Moist Mocha Cake

Cooking spray 3/4 cup whole-wheat pastry flour 1/2 cup all-purpose flour 1/2 cup Dutch processed cocoa 1/4 teaspoon salt 1 teaspoon baking soda 1 teaspoon baking powder 2 tablespoons butter, melted 2 tablespoons canola oil 2 eggs 2 egg whites 1 1/2 cups lowfat yogurt 2 teaspoons vanilla extract 3/4 cup granulated sugar 1 tablespoon espresso powder, dissolved in 1 tablespoon of hot water 2 ounces good-quality dark chocolate 1 (8-ounce) bar Neufchatel cheese (reduced fat cream cheese), softened 1/3 cup confectioners' sugar 1 teaspoon espresso powder dissolved in 1 teaspoon hot water 1 teaspoon coffee liqueur or vanilla 1 small square chocolate