"May I please have one of those biscuits?" asked Alice rather timedly, rather taken aback by the sight of her present company.

"A biscuit?? Oh, I don't know. Those are the March Hare's special un-birthday biscuits, don't you know. Can she have a biscuit, March ?" asked the Hatter.

"A biscuit?? One of mine? Hurmph. Ok, I'm thinking of an integer from one to three (inclusive). If you get it, you can have a biscuit. If not, I'm afraid you'll just have to leave" said the March Hare, leaning back.

"Oh goodness, I don't know" said Alice worriedly. "Couldn't I just get a hint?"

"Oh, all right..." the March Hare sighed. "You get to ask me one yes-or-no question, that's all"

Alice thought for a moment, then smiled, knowing exactly what to ask.

What question should Alice ask?

I see were you are coming from. So Alice could ask the Mad Hatter to ask aloud the March Hare what the integer is (or guess at it till he got it right), then ask if that number of the Mad Hatter.

The only other thing I can think of is based off of this statement:

"If you get it, you can have a biscuit."  The Hatter never specifically asked for Alice to guess the integer he was thinking of. All he said was that he was thinking of an integer and if Alice got the biscuit she could have it.

So Alice would ask (the Mad Hatter this time) if she could have one.