"To your transformation of me." It's the polar opposite of their relationship in their dreams, and Hannibal has to appreciate the irony of it.
"I remember in one of our dreams. I told you that no matter how well I thought I knew you, I could never entirely predict you. I could feed the caterpillar, whisper through the chrysalis, but what hatches follows its own nature and is beyond me.
Here, however, I'm not so sure. I was already on my way to my becoming, but without you there to whisper to me, I never would have been fully realized. I want to thank you for that."