An Etymological Dictionary of the German Language/Annotated/Kuchen
Kuchen, masculine, ‘cake,’ from the equivalent Middle High German kuoche, Old High German chuohho, masculine; compare Middle Low German kôke, Dutch koek. Besides these forms with old ô in the stem (compare Anglo-Saxon cœ́čil, Middle English kêchel, ‘little cake,’ English dialectic keech) there occurs in the Scandinavian and English languages an apparently graded form with a — English cake, and the equivalent Scandinavian kaka, feminine. This gradation seems to point to a Teutonic origin of the cognates, yet their relation to the Romance class (Catal. coca, Rheto-Romance cocca, Picard. couque, ‘cake’), connected with Latin coquus, coquere (Anglo-Saxon côc, Old High German chohhôn), is not clear. Moreover, on the assumption that the word was borrowed, ô in Old High German chuohho would correspond exactly to the ô in Anglo-Saxon côc, ‘cook.’