Did not expect the egg nog flavour to be as tangible as it is. I get a feeling it took a lot of work to develop the finely tuned balance of this cocktail.
As several other commenters, I used cardamom pods instead of bitters. A little dash of orange bitters will also go well with the rest.

Amazing how the eggnog-aftertaste of Advocaat survives to the vanilla-gin sour first kick, even with such a small amount of it. Worth the try. Well balanced also, at least for my taste.

Super delicious! This cocktail is on the sweet side, but it's absolutely delightful as an after-dinner dessert drink —or an anytime drink if you like them rich and full-bodied.

I have used cardamom pods intend of bitters and it is still a very tasty cockail