In a mixing bowl, beat shortening with an electric mixer on medium to high speed for 30 seconds. Add granulated sugar, baking powder, ginger, baking soda, cinnamon, and cloves. Beat until combined, scraping sides of bowl occasionally. Beat in molasses, egg, and vinegar until combined. Beat in as much of the flour as you can with the mixer. Using a wooden spoon, stir in any remaining flour. Divide dough in half. Wrap each half in plastic wrap; chill dough about 3 hours or until easy to handle.
Preheat oven to 375 degrees F. Grease a cookie sheet; set aside. On a lightly floured surface, roll half of the dough at a time until 1/4 inch thick. Cut with 2- to 3-inch gingerbread people-shaped cookie cutters. Place cutouts 1 inch apart on the prepared cookie sheet.
Bake for 7 to 8 minutes or until edges are lightly browned. Let stand for 1 minute on cookie sheet. Transfer to a wire rack and let cool. Pipe designs on cookies with tinted Royal Icing.
In a mixing bowl, stir together powdered sugar, meringue powder, and cream of tartar. Add warm water and vanilla. If desired, tint with food coloring. Beat with an electric mixer on low speed until combined, then on high speed for 7 to 10 minutes or until very stiff. Add 2 to 4 tablespoons additional water, 1 teaspoon at a time, until icing reaches desired consistency. Makes about 3 cups.