A common pet name
or nick name
for boys named Patrick. Usually it starts out as Pat, then evolves into Patty, and then finally ends up being Patty Cakes. Usually only sisters, mothers or girlfriends would ever dare to use such a nicname for the Patrick in their lives.
Patty Cakes, you are amazing. (girlfriend)
Yesterydat, me and Patty Cakes went out to the mall, then for supper! (girlfriend)
Patty Cakes, can you help me do my homework? (sister)
Look at my Patty Cake, isn't he a handsome little boy? (mother)