@Polonius3 In Polish end piece of bread is "piętka"(a heel) and "kromka" is a slice of bread however in Poznań "kromka" is exactly end piece of bread. Usual "kromka" becomes "pajda" in Poznań. :)
Thank you, barbk! I couldn't remember what my Slovak baba and mom called the heel piece and you are right! It was krunka! I can now sleep well tonight. :)
@MoogleSensei 7 years later. My mother and grandmother called it the same thing. Klumpka or klumka. Who knows what other lies I've been living with? :)
Strictly by ear (from my mother) crunka; the end piece nobody liked. And, strictly by ear (from my father) I (and my siblings) we were all "dupa kids". crun-ka