Combine dry ingredients in a food processor (or with an immersion blender).
Add extract, zest and juice.
Pulse until combined.
Knead the dough briefly and roll into a log.
Wrap in plastic wrap and keep refrigerated for a month (or frozen for 6 months).
Take out any time and let it get to room temperature before your child molds it into the creatures of his imagination. (You can find edible googly eyes at my favorite NYC Cake Shop: http://www.nycake.com)