There are endless possibilities Lego-themed cake, especially if you're doing all fondant. However, we like buttercream, and at the end of the day, I figured a wild pack of 8-year-old boys wouldn't care whether or not there was a ball border or my other idea, Lego brick cutouts, so I did a plain buttercream cake, then made Legos using chewy granola bars cut in half and covered with fondant. I cut out the circles for the bricks with the small end of a Wilton No. 12 tip. I finished with a candle and my son's choice of Lego guys.