Prepare the Honey Syrup: In a small saucepan, combine equal parts honey and water (e.g., 1 cup honey to 1 cup water). Heat over low heat, stirring until the honey dissolves into the water. Allow the syrup to cool before using.
Prepare the Garnish: Cut a thin strip of grapefruit peel for the twist. Be cautious not to include the bitter white pith.
Prepare the Cocktail: In a cocktail shaker, add the bourbon, fresh grapefruit juice, and honey syrup. Fill the shaker with ice.
Shake and Strain: Shake the ingredients vigorously for about 10-15 seconds. This chills and dilutes the drink slightly. Strain the mixture into a chilled cocktail glass.
Garnish: Express the grapefruit twist over the cocktail by giving it a twist over the glass, releasing the citrus oils. Optionally, drop the twist into the drink as a garnish.
Serve: Serve the Brown Derby cocktail immediately while it's still cold.