In a large bowl mix sugar, meringue, and cocoa.
Add water, and beat on low about 10 minutes.
Add black food coloring until color is evenly distributed in the frosting.
Melt 4 ounces of white chocolate melts.
Pour into a piping bag and cut a small hole at the tip.
Cut wide straws to desired chalk length.
Squeeze chocolate into the wide straws.
Add a little white sugar to the bottom of a bowl to prevent the chocolate from coming out the other side of the straw.
Make sure to fill straw full of chocolate so you end up with a solid piece of chalk.
Place in the freezer for 10 minutes.
Use a rod knife, sharpening steel or dowel rod to get the chocolate out of the straw.
If you want the lettering to come out more crisp, you can use stencils and melted white chocolate to write on the chalkboard cookies.
These chalkboard cookies with edible chalk work with any homemade sugar cookie recipe!