When I was at university, my boyfriend had a signature drink which we called lemon vodka, that he would make for student house parties. It was so good that it gained him quite a reputation.
Three days before a party, he would take his trusty tupperware bucket, fill it with a couple of litres of vodka, some sugar and a kilo or two of lemons, simply halved. As his secret recipe would dictate, periodically more sugar would added, a little more lemon and I suspect, more vodka. The resulting liqueur was so potent but you didn't realise quite how so until your hangover promptly informed you the next morning.
Despite this infamy (or rather, probably, because of it) this tub would then be very carefully transported to whatever party, accompanied simply by some plastic cups. Quick and effective, it became the reason for him reliably being the first person to know of a party in the offing and I'm not denying it may also have played a certain part in our courtship...
I'm now playing around with creating more sophisticated version of that memory.
This limoncello, for that simply is what it is, is no more than a step up from Joe's old recipe. Lemon peel (careful not to include any pith) macerated in vodka, a little simple syrup added and somewhat diluted because it'll be drunk straight.
I used 80 proof vodka, although I was tempted to use 100 proof and then dilute it down. I happened to have Absolut. The half-finished bottle had been hanging around for a while and it's something I drink so rarely that I decided that it would make the perfect base alcohol for my limoncello.
zest of 6 lemons
After a week or two (depending on how lemony you want your finished drink to become - and also on your patience levels) decant to filter out the lemon peel, and then simply pour the liquid back into the bottle and fill the rest of the bottle up
... with simple syrup and pure water.
Keep in a cool, dark place and drink very chilled as soon as the sun comes out.