Where does “Appelküüsche” come from?

Appelküüsche (Central Franconian) comes from Central Franconian -che, from Middle High German -ichin, from Old High German -ihhīn, from Proto-Germanic -ikīną, from Proto-Germanic -ikaz.

Ancestry of “Appelküüsche”, step by step

Step	Language	Word	Meaning
1	Central Franconian	-che	forms a diminutive noun
2	Middle High German	-ichin	—
3	Old High German	-ihhīn	—
4	Proto-Germanic	-ikīną	—
5	Proto-Germanic	-ikaz	—

Every word from Proto-Germanic -ikaz →Every word from Central Franconian -che →Every word from Middle High German -ichin →