What is this the smell of?/Of what is this the smell?

[navi tasan]

Are these correct?

1) What is this the smell of?
2) Of what is this the smell?

I enter a restaurant. I feel the pleasant smell of a food, which I assume to be delicious. I asked the waiter...

 

[5jj]

1.. Grammatically possible, though I'd never say it. I'd go for "What's that lovely/delicious/etc smell?"
2. No.

 

[Tarheel]

What's that aroma? What's cooking?

That smells good. What is it?