1Place mini paper baking cup in each of 12 mini muffin cups. In large bowl, mix baking soda and citric acid; stir in 2 drops orange essential oil. Spritz witch hazel over mixture until dry powdered product easily sticks together.
2Divide mixture among muffin cups; press into cups. Let dry 1 to 2 hours.
3In medium bowl, mix meringue powder into warm water. Add powdered sugar and cream of tartar. Beat with electric mixer on medium speed 5 minutes or until stiff peaks form. Stir in 3 to 4 drops orange essential oil.
4Spoon mixture into decorating bag fitted with desired dip (or resealable food-storage bag with tiny corner cut off); pipe “frosting” onto bath fizz “cupcakes”. Let dry before packaging.