Take the jigger and measure out .5 oz of lime juice. Toss the lime juice into the mug.Note: Alternatively, if you can't measure in ounces. Add 1 tbs of Lime juice.
Take the jigger and measure 4 oz of Ginger Beer. Toss the Ginger beer into the mug.Note: or, you can add ½ a cup if you don't have a jigger to measure in ounces.
If you'd like to top it off with club soda, do so now. Pour the club soda directly into the mug. Or, use add 2 oz with the jigger (or 4 tbs).
Toss a spring of mint on top and enjoy!
Notes
If you don't have a jigger and/or don't want to measure in ounces:.5 oz of Lime juice is 1 tbs4 oz of Ginger beer is ½ cup2 oz of club soda is 4 tbs