I heard once that this verb (원하다) is not really that used commonly among koreans, but instead they used the "~고 싶다" to say what they want. For example, let's say you want an apple, so "사과를 먹고 싶어요?". I heard that from Talk To Me In Korean, the Youtube channel. I hope someone finds it helpful
You can use 갖고 싶어요 with nouns. This way of saying "I want.." is much more common than 원해요 (By the way, 원해요 sounds kind of poetic in my opinion and you would only use it if you REALLY want something or someone, if you long for something or someone. It has a stronger feeling).
Example using 갖고 싶어:
그 원피스 진짜 갖고 싶어 (I really want that dress)
Yes because ~고 싶어요 needs a verb stem to go with it. For example, 막다 means to eat and to make 막다 a verb stem you need to remove ~다 and you're left with 막. Now for the sentence you used it would be 가람 씨, 뭐 먹고 싶어요? Meaning "Garam what do you want to eat?" Hope this helps clear things up a bit
A scene from Partners in Crime. Next victim's home?
가람? Are you still here? Who is there?
누구 거가에? [ A door creaks]
누구세요? [Menacing music]
Oh, it's you, the best of NFS! 가람 씨, 뭘 원해요?
OMG!!! Am I finished? Why are you always on time! But, of course!
Garam leaves with a smile on his face. Café Bulgogi's nuna makes the best veggie soup in Pine Bluff.
... 그러나 물론입니다!