Malted Chocolate Pudding Cake

INGREDIENTS

• 2 teaspoons pure vanilla extract
• 1/4 cup Dutch processed cocoa powder, plus 2 tablespoons
• 1/3 cup whole-wheat pastry flour
• 2 teaspoons baking powder
• 1 1/2 cups boiling water
• 2 tablespoons unsalted butter, melted
• 3/4 cup packed light brown sugar
• 1 cup chocolate malt powder, such as Ovaltine
• 1/2 teaspoon fine salt
• Nonstick cooking spray
• 1 large egg white
• 2/3 cup all-purpose flour
• 1/2 cup low-fat (1 percent) milk
• Confectioners' sugar, for dusting, optional