This fresh take on a classic uses gin and genshu sake (a higher proof variant with lots of flavor), both from Akashi city in Hyogo, Japan. Vermouth normally supplies aromatics, in this drink they are instead in the garnish (a spiced pickled onion), creating a delicate cocktail with a savory finish, perfect as an aperitif.
To prepare the spiced onions: Pour the pickling liquid from the onions into a small saucepan, add the spices and mirin and heat until just below a boil. Combine with the onion and put them back in the original jar. If you're using regular onions you may want to add a bit more mirin or some sugar, the liquid should be fairly sweet. Allow to cool to room temperature and then store in the refrigerator. They are ready to use as soon as they are cool, but will continue to deepen in flavor.
For the cocktail: In a mixing glass filled with ice add the gin and sake and stir until ice cold. Strain into two coupe or martini glasses and garnish with spiced onions.
* rakkyo are a traditional Japanese pickled onion often eaten with curry. They have a more delicate texture than western pickled pearl onions.
Variations & Ideas:
Add a bit of pickling brine to the cocktail for a richer cocktail. I like to add a zest of fresh yuzu (which is in season), or lemon to add some brightness. You can omit the onion if you like.
Play with the proportions of sake and gin. Some people prefer a drier (less sake) cocktail, some people like to push it closer to 50:50. Experiment and find out!
Regarding shaking. I'm not opposed to it at all, but it does make ice chips that alter the dilution and texture of the drink. I recommend shaking individual portions, straining them into a chilled glass, and consuming them more quickly.
Other ways to use the onions:
Slice the onions into quarters and add to your favorite salad or to a stir-fry
Use some of the brine to make a salad dressing
When the onions are finished use the brine to pickle other vegetables, asparagus tips and/or baby turnips both take well to the mixture