In a large mixing bowl, cream butter and confectioners' sugar until light and fluffy.
Beat in egg and vanilla. Gradually add flour.
Divide dough in half. Cover and refrigerate for 2 hours or until easy to handle.
On a lightly floured surface, roll out one portion of dough to 3/16-in. thickness.
Cut with floured cookie cutters.
Place 2 in. apart on ungreased baking sheets. Bake at 375° for 5-7 minutes or until set.
Cool for 2 minutes before removing from pans to wire racks to cool completely.
Repeat with remaining dough.
For frosting, in a small mixing bowl, beat the confectioners' sugar, water and meringue powder on low speed just until combined.
Beat on high for 4 minutes or until soft peaks form.
Add corn syrup; beat 1 minute longer.
Tint with food coloring of your choice.
Cover frosting with damp paper towels or plastic wrap between uses.
Spread and/or pipe frosting on cookies. Let stand until set.