The basic recipe is just that - very basic. Make up a packet of jelly, using between a quarter and half of the amount of water suggested. Top up with as much vodka as you like (or can handle).
A True Art
However, the art of vodka-jelly-making is not an easy one. There are several factors to be weighed up - each depending upon your own personal taste:
How strong is the vodka?
How thick is the jelly (without vodka)?
Do you want to be able to taste the vodka much, or not at all?
Should anything else be added to the jelly, such as fruit?
These, and several other minor points have to be taken into consideration in order to create the perfect vodka jelly - one that is perfectly set (and has the perfect wobble factor), and also the perfect flavour and texture.
The only way to find the recipe for the perfect vodka jelly is trial and error - as everybody has a slightly but significantly different idea of perfection.
It's good fun finding it though.