Through The Looking Glass by Lewis Carroll Chapter 7 Page 17

‘if you’ll believe in me, I’ll believe in you. Is that a bargain?’

‘Yes, if you like,’ said Alice.

‘Come, fetch out the plum-cake, old man!’ the Unicorn went on, turning from her to the King. ‘None of your brown bread for me!’

‘Certainly — certainly!’ the King muttered, and beckoned to Haigha. ‘Open the bag!’ he whispered. ‘Quick! Not that one — that’s full of hay!’

Haigha took a large cake out of the bag, and gave it to Alice to hold, while he got out a dish and carving-knife. How they all came out of it Alice couldn’t guess. It was just like a conjuring-trick, she thought.