Printed at 0.1 mm, slightly hotter in PETG (so get a glossy finish).

Print the hollow backing and T bar in one colour and the round “dot” insert in another.

I did transparent and black.

Press fit the dot into the backing (it's a tight fit and doesn't require any glue).

Press fit the T into the back of the button. It is angled so as to keep orientation when worn through cuff holes (like many cuff links are).

Add a small (i.e. 1-2 drops) of superglue to the back of the button where the T meets the button. It should be pulled through the small gap in the back of the button and glue all 3 pieces together.

Lastly, enjoy the party… shaken…not stirred!