To make this Iron Man Birthday Cake Design I started with a regular 9×13 sheet cake nd iced it white in buttercream. To make Iron Man’s face I printed out a coloring book image that I sized to fit the cake and printed in the mirror image. Then I followed the directions on this site for making a frozen buttercream (though I used the Wilton recipe for the buttercream, and I used Duncan Heinz Homestlye Chocolate Frosting dyed black for the outlines).
I actually did all the black outlines first and smoothed them from the back as much as possible. Then I put the whole thing in the fridge before adding the other layers of buttercream all at once. That way the black spots wouldn’t smear. Once I took it out of the freezer & put the image onto the cake I put the WHOLE cake, with the wax paper still on, back into the freezer for another 30 minutes to make the wax paper removal easier.
To make the text I used some letter magnets pushed into the icing gently to get the outline. Then I filled the outlines in with yellow buttercream and smoothed them with my finger dipped in cornstarch. Then, using tip #1 I outlined the text with the chocolate icing.
The frozen buttercream technique was really not hard at all, and produced amazing results. I highly recommend trying it!!