Mixing

1. Use the correct ratio of vegetable shortening or butter to powdered sugar in your buttercream icing, as called for in your recipe. Use about 1 cup shortening to 1 lb. powdered sugar. Icing made with too little vegetable shortening or butter is prone to cracking. If you have had problems with your recipe in the past, add an extra tablespoon of vegetable shortening or butter to keep your icing moist.

2. Incorporate whole milk into your icing recipe instead of water or milk with a lower fat content. The additional fat in whole milk gives icing a more creamy texture and allows more time to apply it to your cake before it begins to dry out.

3. Measure your wet and dry ingredients with the proper tools. Always use liquid measuring cups for your wet ingredients and dry measuring cups for dry ingredients. Use measuring spoons for small amounts of ingredients, not serving spoons or other utensils. Incorporating too little liquid in your recipe, because you used the wrong measuring cup, can cause cracks in the icing on a cake.

4. Incorporate a couple drops of vinegar into your icing recipe to prevent dry, cracking icing. The acidity of the vinegar keeps the sugar in the icing from clumping and becoming brittle. Adding a bit of baking soda also works.

5. Repair cracked fondant by applying vegetable shorting directly to the damaged area. Use a spreader or spatula to scoop up and apply a small amount of vegetable shorting along the crack. Blend it into the fondant using a circular motion.

Handling

1. Apply an adequate amount of icing to your cake. Thin layers of icing dry out quickly and are prone to cracking. Spread on a thin coat of icing to seal crumbs to the cake. Allow that layer to set up and then spread on a thicker top layer of icing.

2. Move your cake as little as possible. Picking up a cake can cause dry icing to crack. If you have to move a cake, always place a hand under its bottom center for support; picking it up by the edges causes it to flex and will crack the icing.

3. Support your cake with the proper size and thickness cake board - larger cakes require bigger and studier cake boards. Using a thin cake board under a heavy, large or multilayer cake can cause the board to flex and result in cracks in the icing.

4. Keep your cake away from drying elements. Don't put it near a heat vents, air conditioning units, fans or open windows. Any dry or blowing air can dry out the icing and promote cracking.