More on Haver-Cakes from Infoplease:

• Haver-Cakes - Haver-Cakes Oaten cakes (Scandinavian, hafre; German, hafer; Latin, avena, oats). Source: ...
• Haversack - Haversack Strictly speaking is a bag to carry oats in. (See Haver-Cakes.) It now means a ...
• Dictionary of Phrase and Fable: H - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "H"