The typical brewhouse cuisine: Drinking "Kölsch" an eating "Himmel un Ääd" (Heaven and earth). Here are some local specialities you can eat in Cologne:
Halver Hahn - it is not chicken! It's a rye roll with Dutch cheese, butter and mustard.
Himmel un Ääd (Heaven and earth) - Mixture of apple pieces (heaven) and mashed potatoes (earth)
Flönz - "Blutwurst", black pudding
Kölsche Kaviar - black pudding (Flönz), rye roll and onions
Rheinischer Soorbrode - sometimes orign horsemeat, but in general a beef dish with a special sauce of raisins, dumpling and red gabbage
Hämmche - boiled knuckle of pork, mashed potatoes and sauerkraut
Halber Meter Bratwurst - half a metre of orign German bratwurst