Buttercream Transfer was one of the first techniques I learned at age 12. Using a coloring book page, I cover the print with a piece of wax paper and tape it all to a piece of card-broad.
Start by outlining the drawing in buttercream, (I prefer to always outline in black). Then working carefully, fill in the colors of your choice. For the face you must fill in the eyes, nose and mouth before added the skin color. If you want to added dimension to the long hair you must add the highlights before filling in the main color. If you need to add a number to the jersey, you must also add it before the main color.
It is important to remember that the drawing will be in reverse when it is applied to the cake. If your drawing is how you want the final outcome to look as you are looking at it, you must turn over your original picture. Using a pencil, outline the character as well as any details the will help you to know how to fill in the picture. Apply the wax paper to the pencil drawing and follow as above.
Once you have filled in all the areas, place the entire drawing with the wax paper and card board in the freezer. This type of art can be done up to a week in advance of the finished cake.
Here I have a 13" x 9" cake covered in buttercream.
First I airbrushed the background, green for the grass and clouds in the sky. At this point I chill the cake for an hour or so. At the end of the hour, I remove the buttercream transfer from the freezer, carefully remove the tape and lift the wax paper placing the buttercream drawing to the buttercream on the cake. Your wax paper should now be on top facing you. Again chill the cake for an hour and then you can remove the wax paper, add your message and trim the borders of the cake.