The Collaborative International Dictionary
Clapcake
Clapbread \Clap"bread`\, Clapcake \Clap"cake`\, n.
Oatmeal cake or bread clapped or beaten till it is thin.
[Obs.]
--Halliwell.
Wiktionary
clapcake
n. (context obsolete English) oatmeal cake or bread clapped or beaten until thin