A Piece of Cake - album - was created in 1996.
The Cake Eaters was created in 2007.
Cut the Cake - album - was created in 1975-06.
Cake or Death - album - was created in 2006-02.
The Cake Sale - album - was created on 2006-11-10.
Piece of Cake - novel - was created in 1983.
Piece by Piece - Katie Melua album - was created in 2004.
Piece by Piece - John Martyn album - was created in 1986-02.
The Missing Piece - Twins album - was created in 2005.
Three Piece Suite - album - was created in 1994.
Piece of Mind - Tela album - was created on 1996-11-05.
The Missing Piece - Gentle Giant album - was created in 1977-05.
A piece of cake is simply called (and spelled) "a piece of cake." It may also be called "a serving of cake" or "a slice of cake."