"The stew and the Goulash soup are very delicious."
Translation:A pörkölt és a gulyásleves nagyon finom.
When you have a compound subject like One Singular Thing and Another Singular Thing ("the stew and the soup") then you can use a singular predicate (whether it's a verb, or a predicate nominative like this).
When we list a certain amount of food then the adjective "finom" doesn't change in plural.
But if we would say: These foods are very delicious. - Ezek az ételek nagyon finomak.