You can omit the small amount of coffee liqueur without drastically changing the flavor. Contemporary Mexican chefs often add ground red pepper to their chocolate desserts; leave it out if you want a more traditional taste.
3 tablespoons granulated sugar
1/2 cup granulated sugar
1/4 cup unsweetened cocoa
2 tablespoons all-purpose flour
1 teaspoon ground cinnamon
1/8 teaspoon salt
1/8 teaspoon ground red pepper (optional)
3/4 cup fat-free milk
3 ounces bittersweet chocolate, chopped
1 teaspoon vanilla extract
1 teaspoon coffee-flavored liqueur (such as Kahlúa)
1 large egg yolk
1/4 teaspoon cream of tartar
6 large egg whites
2 tablespoons granulated sugar
Powdered sugar (optional)
How to Make It
Preheat oven to 375°.
Coat 8 (6-ounce) ramekins with cooking spray; sprinkle with 3 tablespoons granulated sugar.
Combine 1/2 cup granulated sugar, cocoa, flour, cinnamon, salt, and pepper, if desired, in a medium saucepan. Gradually add milk, stirring with a whisk until smooth. Bring to a boil over medium-high heat; cook 1 minute, stirring constantly. Remove from heat; add chocolate, stirring with a whisk until smooth. Place chocolate mixture in a large bowl; stir in vanilla, liqueur, and egg yolk.
Place the cream of tartar and egg whites in another large bowl; beat with a mixer at high speed until foamy. Add 2 tablespoons granulated sugar, 1 tablespoon at a time, beating until stiff peaks form. Gently stir one-third of egg white mixture into chocolate mixture; gently fold in remaining egg white mixture. Spoon evenly into ramekins; sharply tap ramekins 2 or 3 times on counter to level. Place ramekins on a baking sheet.
Bake at 375° for 30 minutes or until puffy and set. Sprinkle with powdered sugar, if desired. Serve immediately.