my contribution, my signature to the evening

[Coffee Break]

I encountered the expression "my contribution, my signature to the evening", but am struggling to understand it. Could you please let me know what it means? Here is the excerpt:

I held her hand a touch longer than is usual, to say I had gotten the message, but let it go sooner than warranted, fearing I’d invented the message.

That was my contribution, my signature to the evening, my twisted reading of a plain handshake. If she knew how to read me, she’d see through this affectation of nonchalance and catch the other, deeper nonchalance, which I am reluctant to dispel especially in the presence of someone who, with three words and barely a glance, could easily hold the key to all my hideaways.

- André Aciman, Eight White Nights, First Night

This is a novel published in the United States of America in 2010. It is narrated by a nameless male protagonist. He meets Clara at a Christmas party in Manhattan. Now the protagonist is reading into his handshake with Clara.

I wonder what the underlined expression means.
I vaguely understand that, by "my contribution", he contributed something to the evening (in that he provided something to the evening), but I just cannot understand what his "signature to the evening" might mean.

 

[Tarheel]

This writer has a unique style. He's very inventive with the language. So you should expect to keep seeing that kind of thing. As for the phrase in question, I imagine it's his contribution to the evening.

 

[Coffee Break]

@Tarheel,

Thank you very much for the explanation.
Indeed, I see a very unique style throughout the book!
So the protagonist made contribution to the evening.

But, as for the meaning of "signature", would it mean that he signed his name to the evening...? Or would it mean his feature/characteristic regarding the evening? Or perhaps, the musical arrangement of the evening...? I am struggling to find an adequate meaning for "signature" here.

 

[SoothingDave]

This was his personal touch.

 

[Tarheel]

Two things. One, it's a common usage of"signature". It should be in all the dictionaries. Two, the phrase " very unique" does appear quite often. However, if something is one of a kind it cannot have more of that quality (uniqueness) or less of it.