Place the apple cider and ginger beer in the fridge before you start. Cold ingredients keep the drink crisp and stop the ice from melting too fast. I also pop my copper mug in the freezer for a few minutes when I have time.
Cut a lime into quarters and squeeze one piece into a small bowl or straight into your mug. Remove any seeds so they don't sneak into your drink. Fresh juice tastes much brighter than the bottled kind.
Pour 1 1/2 ounces of vodka using a jigger or shot glass. That is about one standard US shot, or three tablespoons. Measuring keeps the drink balanced, so the vodka never overpowers the cider.
Add a generous scoop of ice to your copper mug. Fill it nearly to the top. More ice means a colder drink and slower dilution, which I think makes the last sip as good as the first.
Pour in 4 ounces of apple cider, then the vodka and the lime juice. Give it one slow stir with a long spoon. This mixes the base without knocking out any of the fizz you will add next.
Slowly pour in 4 to 6 ounces of ginger beer until the mug is full. Pour it down the side of the mug or over the back of a spoon. That small trick keeps more bubbles in your drink.
Add a thin apple slice, a cinnamon stick, a lime wheel, or a small rosemary sprig. Serve it right away while the bubbles are lively. Take a sip, smile, and enjoy that spicy apple flavo