It's not worth it to go there for lunch or dinner, but if you are at Barbarossaplatz - one of the main traffic junctions in Cologne city centre - it's ok to have a snack or a coffee. The snackbar resides immediately at the lightrail station. They make really good coffee and have 3-5 vegan snacks. One viet-soup (it's ok, but not very good), summerrolls (good!) samosas and a salty soyapancake.
No cakes or vegan bakery available.
Cons: No Cakes or so