Pattycakes this is something i have never actually done however i found this online and thought i would share it with you.
HOW TO COVER A HEART SHAPED CAKE IN FONDANT
1. Bake your cake. Once cooled, place it on the cake board and flatten off the top if it has mounded. Brush away any crumbs and unsightly bits. I turned my cake over so that it was bottom up, as it made for a much smoother surface.
2. Mix up a butter icing--start with 1 cup of icing sugar, 1 tbsp melted butter and 1 tsp vanilla essence. Add more icing sugar, or water, until it comes to a medium thickness, smooth icing. You don't want it to be runny, but you don't want it to be too thick that it pulls crumbs off the sides of the cake. Smooth it evenly over the surface of the cake with the flat of a butter knife. Use the icing to cover and fill any gaps and holes that may have formed when removing the cake from the tin.
3. Set the cake aside. Take the Rolled icing and kneed with your hands until it becomes smooth and pliable. You may want to microwave it very quickly (5-10 seconds on high) if it's a cold day and it has become hard. Lightly flour the rolling surface with a little icing sugar and roll to desired size and thickness. It's a good idea to lift and turn the fondant after every few rolls to get an even surface and good shape, and to make sure the fondant has not stuck to your rolling surfaces.
4. Once you have the correct size and desired thickness, lift the fondant and partially drape it onto the rolling pin for stability. Gently lay it over the butter icing-covered cake, removing the rolling pin as you go. The rolling pin helps to avoid any stretching of the fondant while laying it on your cake. With your hand gently smooth the top, then the bottom corner/ point of the cake first.
5. Continue to smooth the fondant over the cake with your hands. You can see in the above picture that although the fondant has been laid nice and flat over the cake, there are areas where the fondant bunches (see top right and left sides of the cake). To fix this unevenness and to prevent a bunched surface, just run your hand around the rest of the cake to smooth the fondant, then lift these problem areas away from the cake and then smooth downward to get rid of the bunching effect.
6. Now that the surface is smooth, ensure the bottom edges meet the board. If they are a little short, do not stress, as this un-neatness can be covered with a ribbon or pipped icing around the edges if need be. With a small, sharp and non-serrated knife, cut the excess icing from the board, about 1 cm from the cake. Don't cut too closely as you may be surprised to find the fondant floating at the edge. Neatly tuck this 1 cm of fondant towards the base of the cake, and cut away any further overhang if any exists.
7. Collect the residual fondant and roll it into a ball. Wrap it in cling wrap and run it over the whole surface of the cake to smooth it for a final time. Some people prefer to use a flat smoothing device especially made to perfect the surface, but this home made little ball of fondant works brilliantly too if you don't happen to have one.
8. Clean away any residual icing sugar, fondant or stickiness from the board with a damp cloth or tissue. Measure the sides and cut a piece of ribbon that will fit around any messy edging if desired. I simply held the ribbon on the cake with a sewing pin (with a coloured ball head so it was visible enough not to be mistaken for cake) pressed into the top indentation of the cake.
http://lickthatspoon.blogspot.com/2013/06/how-to-cover-heart-shaped-cake-in.html
