Prison and Chocolate Cake by Nayantara Sahgal. Watch out for the review of this magnificent book- it'll be up by tomorrow =)
Now, the teaser, as promised:
Mummie explained that they had come to take Papu to prison, but that it was nothing to worry about, that he wanted to go. So we kissed him goodbye and watched him leave, talking cheerfully to the policemen. We ate our chocolate cake, and in our infant minds prison became in some mysterious way associated with chocolate cake.