About Rolled Buttercream: You will find that it is a softer covering than Fondant. It also stands up to heat well, and keeps nicely (tightly wrapped) in the refrigerator. Do bring to room temperature before using.
Recipe will cover a 9" round, 2-layer cake with a bit extra:
1 cup Crisco (shortening) 1 cup Karo clear corn syrup 1/2 tsp fine grained salt 1/4 tsp lemon oil* 1/4 tsp orange oil* 2 lbs. (7 to 8 cups) powdered sugar * or 1/2 tsp total of any citrus oil(s) Paste food coloring, if color is desired
Using a heavy-duty mixer, measure all ingredients into the bowl. If you wish to color the entire batch, add paste color at this time. (Make slightly darker than desired finished color). Beat till almost mixed together; the texture of soft pie dough. At this point, take out a small amount & store tightly wrapped in a plastic bag. This is used to soften icing if it gets too stiff (water cannot be added). Turn out onto countertop lightly dusted with powdered sugar. Knead by hand for 2 - 3 minutes till all mixed. Check consistency frequently by taking a small piece & 'polishing' it with the palm of your hand. When it becomes glossy without sticking to your hand, enough sugar has been added. If it feels sticky, knead in more powdered sugar if it does.
Store tightly wrapped in double plastic bags in the frig. Allow to age at least 2 - 3 days. It may be kept, tightly wrapped for several weeks. Bring to room temperature before using.
To prepare the cake, layer & trim top edge so it is rounded. Crumb coat lightly with regular buttercream. Be sure it is smooth, as any imperfections will show thru the rolled icing. Remove room temperature icing from bags, and knead for several minutes. Roll out between sheets of plastic (or on a counter or board dusted with a mixture of powdered sugar & cornstarch. Be sure to lift & turn, redusting icing frequently to avoid sticking. Dust rolling pin, also.) until approximately 1/4" to 3/8" thick & large enough to cover top & sides of cake. Flip over & remove bottom plastic. Pick up top plastic with icing on it, turn over carefully & center over crumb coated cake. Carefully start to peel plastic away from icing. Fullness around sides can usually be worked out or cut off & smoothed with your hands. If the icing should tear, just put a small piece over the hole & blend with your hand.