Prepare a lemon slice wheel and set aside for garnish.
Add gin, fresh lemon juice, rich simple syrup, and Angostura bitters to a cocktail shaker.
Add ice and shake hard for 10–12 seconds until well chilled.
Strain into an Old-fashioned glass filled with fresh ice.
Add drops of saline solution over the top.
Garnish with a lemon slice wheel on the rim.
A few drops of saline solution - typically a 20% salt-to-water ratio - is the bartender's secret weapon here, suppressing bitterness and amplifying the aromatic complexity of both the gin and bitters without any detectable saltiness.
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