Measure bourbon, maple syrup and grapefruit juice and pour each into a shaker.
Add small ice cubes and shake until the liquids are mixed and chilled - approximately 20 seconds.
Strain the liquid into a coupe glass.
Express the glass with a grapefruit peel slice before adding it as garnish.
Pro Tips
You can use honey syrup instead of maple syrup.
You can use a lowball glass instead of a coupe glass. If you make this switch, be sure to drop a large ice cube into the glass before you strain the cocktail into the glass.