smash cake
n.— «I noticed two cakes on the table, both obviously courtesy of a bakery. One was quite small in comparison to the sheet cake and was yellow, much like the color of a smiley face. After the hamburgers and hot dogs and a little time relaxing, we were all told it was time for the birthday girl to have a go at her smash cake.» —“This birthday episode really takes the cake” by Susan Kelly in Youngstown State University The Jambar (Ohio) June 21, 2001. (source: Double-Tongued Dictionary)