Combine margarine, baking chocolate, and espresso powder in a medium-size microwavable mixing bowl.
Microwave on High for 1 minute, or until margarine and chocolate are melted.
Stir to blend completely, and dissolve espresso powder.
Set aside to cool slightly.
Use a wire whisk to beat in sugar replacement, fructose, egg whites, and vanilla.
Beat for 1 minute.
Add flour and baking powder; stir until completely blended.
Cover with plastic wrap, and refrigerate for at least 1 hour, or until needed.
Form dough into small balls; then press balls into patties using the palm of your hand.
Spray cookie sheet lightly with vegetable-oil spray.
Place patties about 1 in. (2.5 cm) apart on the cookie sheet.
Bake at 375°F (190°C) for 10 to 12 minutes.
Remove from pan, and, while cookies are still hot, sprinkle with chocolate powdered-drink mix.