Bittered Gin Sling

ice

1 ½ (1.5 fluid ounce) jiggers gin

¾ ounce sweet vermouth

½ ounce lemon juice

½ ounce simple syrup

2 dashes bitters (such as Angostura®)

2 ounces club soda, or as needed

1 (2 inch) piece lemon peel for garnish

Put ice in a cocktail shaker. Pour in gin, vermouth, lemon juice, simple syrup, bitters. Shake well. Add ice to a highball glass. Strain cocktail into highball glass, top off with club soda, and garnish with lemon peel.