I found a recipe booklet at the store yesterday from Land o Lake, issue #61, Cookies & Bars.
Royal Icing
This icing hardens as it dries and is ideal for piping decorations on cooled cookies. Yield 3/4 c.
1 1/.4 c. sifted powdered sugar
1 T meringue powder
2 T warm water
1/4 t cream of tartar
Combine all ingredients in a large bowl. Beat at low speed until moistened. Increase speed to medium. Beat until stiff and glossy (2 to 4 minutes). Add an additional tabelspoon of hot water if too stiff.
Cover bowl with damp paper towel until ready to use or cover with plastic wrap and rerefigerate for up to 2 weeks. To restore texture, allow icing to reach room temperature, then re-beat.

Powdered Sugar Glaze
This frosting hardens on standing and gives cookies a glazed surace for decorating. Yield 1 c.
2 1/2 c powdered sugar
2 T water
1 T butter, softened
1 T light corn syrup
1/2 t almond extract or vanilla, if desired
food color, if desired

Combine powdered sugar, water, butter, corn syrup and flavoring in a small mixer bowl; mix until powdered sugar is moistened. Beat at medium speed until smooth, adding additional water if necessary to achieve desired spreading consistency. Tint with food color, if desired.
Frost cooled cookies. Let stand until hardened (6 hrs. or overnight).
I hope this helps. BTW there are some very interesting recipes in this booklet. www.landolakes.com