In large bowl, combine shortening and molasses; blend well. Add all remaining cookie ingredients; mix well. Cover with plastic wrap; refrigerate at least 2 hours for easier handling.
Heat oven to 350°F. On well-floured surface, roll dough to 1/4-inch thickness. Cut with floured 2 1/2-inch round cookie cutter. Place 1 inch apart on ungreased cookie sheets.
Bake at 350°F. for 6 to 9 minutes or until set. Cool 1 minute; remove from cookie sheets. Cool 10 minutes or until completely cooled.
In 2-quart saucepan, combine water and gelatin; let stand 5 minutes. Stir in sugar; bring to a full rolling boil. Reduce heat to medium; simmer 10 minutes without stirring. Temperature should read 220°F. on candy thermometer. Remove from heat. Add powdered sugar; beat with electric mixer at low speed until foamy. Add baking powder and vanilla; beat on low speed for 5 minutes or until glossy and of spreading consistency.
Spread frosting on underside of each cookie to within 1/8 inch of edges. If desired, decorate cookies. Let stand until frosting is set before storing, about 2 hours.