When the cake is ready, tell her you wanna (talk) eat it, and when she is free for about 2 hours etc. She will know why. She will ask you 'What about?' Maintain her curiosity level.

WAIT! The time to devour it has yet not arrived. Remember the icing? Its yet not done, sweetheart.

Introduce a short time gap. If she's really interested, she will come and ask you, 'Okay tell me, what did you want to discuss?' Tell her that you want something from her that she'll probably not give. Cajole her into agreeing to give you whatever you ask for. Take her promise - The promise has to be taken hand to hand - palm top to palm down. Give her as many indirect clues as you want. She oughtta get the message CLEAR.

Wait & wait. Be patient. She will soon be after you.

Now you have got the icing part on your cake. Sink your teeth in!