This decorative icing dries hard like plaster and is pure white unless tinted with food coloring. It is stiff enough to pipe and makes beautiful filigree, lace, tiny dots, and string work on wedding cakes. Adjust the consistency by adding more or less powdered sugar or a little water. The icing is mostly sugar and not especially delicious, though it is ideal for decorative sugar cookies. Our advice is to use it only when decoration is more important than taste and/or in very small quantities. To avoid the naturally grayish tone that develops during preparation, add to any portion that you want to keep white a slight amount of blue food coloring. Do not use blue in any icing that you plan to color yellow, orange or any other pale, warm tint.

Sift together into a medium bowl:

Beat in a large bowl, or in a stand mixer with the whisk attachment, until stiff but not dry:

Gradually add the sifted sugar mixture and:

until it is of a good consistency to spread. Cover with a damp cloth until ready to use.

To apply as piping or for decorative effects, use a piping bag fitted with a fine plain tip, or cut off the corner of a zip-top bag or the tip of a parchment paper cone. Should you want the icing stiffer, add a little more sifted sugar. To make it softer, thin it very gradually with lemon juice or water.

Stir together in a microwave-safe bowl until thoroughly combined:

Microwave until the mixture reaches 160°F on a thermometer (it should not exceed 175°F), 30 to 60 seconds. (If you need to take more than one temperature reading, wash the thermometer thoroughly or dip it into a mug of boiling water before taking additional readings.) Add and beat on high speed until the icing is cool and holds stiff peaks:

If the icing is not stiff enough, add more sugar. Color, if desired, with liquid, powdered, or paste food coloring; the color will intensify as the icing stands. The icing can be stored in a covered container for up to 3 days; press a piece of wax or parchment paper directly against the surface to prevent drying. The icing can be rebeaten if necessary. To pipe, see version I.