These crepes are best served immediately from the oven.
Place 1/2 cup flour in a medium bowl. Combine 1/2 cup milk, 2 teaspoons sugar, oil, and egg; add mixture to flour, stirring with a whisk until almost smooth. Cover batter; chill for 1 hour.
Coat an 8-inch crepe pan or nonstick skillet with cooking spray; place over medium-high heat until hot. Remove pan from heat. Pour a scant 1/4 cup batter into pan; quickly tilt pan in all directions so batter covers pan with a thin film. Cook about 1 minute. Carefully lift edge of crepe with a spatula to test for doneness. The crepe is ready to turn when it can be shaken loose from the pan and the underside is lightly browned. Turn crepe over: cook 30 seconds on the other side.
Place the crepe on a towel; allow it to cool. Repeat procedure until all of the batter is used. Stack crepes between single layers of wax paper or paper towels to prevent sticking.
Preheat oven to 350°.
Combine 2 tablespoons sugar, cocoa, and 2 teaspoons flour in a small saucepan; stir well. Add 1/4 cup milk and yolk; stir with a whisk. Place over low heat; cook 5 minutes or until thick. Remove from heat. Stir in vanilla. Pour into a large bowl; set aside to cool.
Beat egg whites at high speed of a mixer until foamy. Gradually add 1 tablespoon sugar, beating until stiff peaks form. Gently fold one-fourth of egg white mixture into chocolate mixture, and gently fold in remaining egg white mixture.
Spoon 1/3 cup soufflé mixture into center of each crepe; fold in half. Place filled crepes on a baking sheet. Bake at 350° for 10 minutes or until puffy. Spoon Chocolate Sauce over each crepe; sprinkle with powdered sugar. Garnish with orange rind strips, if desired.