Lemon soju might just be the most popular of the flavored soju drinks that you can have at Korean bars and clubs. For lemon soju, I use a little less than a 2:1 (soju:other stuff ratio), which makes it a bit stronger tasting than my other soju recipes. Using fresh lemon juice and lemonade concentrate/powder does the trick and masks the real (awful) soju flavor. Some recipes call for lemon-lime juice, but I find this makes the concotion a bit too sweet. Try it out and see what you think.
1 cup soju
1 cup tonic
two handfuls of ice
3 tsp frozen lemonade concentrate or lemonade powder
squeeze lemon juice
Blend the ice. Add the rest of the ingredients and blend a bit more. Serve in shot glasses or regular (small) glasses.