I saw an ad from a woman looking for someone that could make a guitar birthday cake. So I gave her a call and told her that, although I had never made a guitar cake before, I could probably pull it off. She agreed.
I baked two 9″ x 13″ cakes, cooled them and cut them lengthwise. I frosted between the layers and chilled both cakes over night in the fridge. The next morning, I drew a basic guitar shape on a piece of cardboard, excluding the neck, and cut it out for use as a template. I placed the cakes one in front of the other, laid the template on top and cut around it. I used the excess cake to assemble the neck of the guitar.
Once I had crumb coated the cake, I covered the body in black marshmallow fondant. The neck was covered in a more flesh-tinted marshmallow fondant. The white part on the guitar body was melted white chocolate. The strum bar and whammy bar were made of gum paste and painted with silver shimmer dust mixed with a little lemon juice.
I used black frosting to write out ‘Happy Birthday” and piped a line around the edge of the white chocolate.
A little tip for black frosting: use chocolate frosting instead of white when you want a black tint. I learned that the hard way.