I find that adding powdered sugar or cornstarch when rolling it out creates the dry elephant skin on fondant. I use shortening when kneading and rolling and it keeps the fondant ver smooth and doesnt dry out as fast. Try not to roll out the fondant too thin and as for repairing cracks you just squeeze it together but you will have to cover it up with something. I use a marshmallow fondant recipe and I love it plus it tastes great too. Here is the recipe I use from Edna de La Cruz:
Marshmallow Fondant with Lemon Juice
16 oz. mini marshmallows
2 Tbsp water
2 tsp lemon juice (fresh or bottled)
2 tsp light corn syrup
1 tsp vanilla
2 lbs (approx 7 C) confectioner's sugar, sifted
1/2 C Crisco or vegetable shortening
Grease microwave proof bowl w/ Crisco. Also grease wooden or heat proof spoon. Pour marshmallows and water into bowl. Microwave for approximately 2 minutes stopping and stirring at 40 second intervals. Mixture should be soupy.
Take out of microwave and immediately add corn syrup, lemon juice and vanilla. Stir well. Sift confectioner's sugar into mixture, one cup at a time. After approximately 6 cups, grease your hands well with shortening and knead the mixture in the bowl. Now grease your work surface well and turn mixture out of bowl onto counter. Sift remaining sugar, re-grease hands, and knead well. If mixture seems soft, add one additional cup of powdered sugar.
Shape into a mound and put a coating of crisco on outside. Double wrap in cling wrap and insert into ziplock bag. Press air out of bag and seal. Allow to rest overnight, but, can be used after sitting for a few hours.
what is the lemon juice for??? just curious...
Lemon juice like acetic acid helps to dry out the fondant. Fondant isn't going to go moldy as it is chock full of sugar which inhibits mircrobial growth. I have had Christmas cakes decorated in November here (the begining of our summer) in Australia and been left out -stored in a cake box in a cupboard throughout January - and it has been fine. The only thing that changes is that the icing gets a bit harder, and as you add alcohol to the fruit cake, it doesn't go moldy either. Back in the day, cooks had to develop methods that would work in our harsh climate and being a part of the British Empire, fondant was the cake covering of choice and fruit cake the choice for celebration cakes because of it's good keeping qualities.
Here is the recipe I use when I make fondant, or plastic icing as it is also known here in Australia.
1 egg white (yes you can use egg white powder or meringue powder)
half a teaspoon of glycerine
125 grams of liquid glucose
strained lemon juice
1.5 - 2kilograms of pure icing sugar (confectioners sugar)
using a wooden spoon, beat egg white lightly and add SIFTED icing sugar gradually to whites.
Beat well following each addition until royal icing consistency
Add glucose and glycerine and more icing sugar till once again it is at royal icing consistency
IF you have added all your ingredients and the mixture is too stiff add a few drops of lemon juice.
Add flavouring or colouring of choice
Place icing on a board and knead the mixture till it is firm and doesn't stick to fingers
Roll out and place over cake.