"Smaker det" was the translation Duo gave to the question "Does it taste good" but where is the "good" in this answer. According to my dictionary Smaker just means taste and det means it so I would have translated this as "Does it taste?".
The "good" is implied. It's a quite common way of asking whether the food was to your liking.
It functions more as a reflexive "Does it taste you well?" (and actually can be reflexive in Norwegian), as it's asking for your subjective opinion - not necessarily whether you think somebody else would like it too.