Into a cocktail mixing glass over ice, add gin, vodka, raspberry syrup, maraschino liqueur, grapefruit bitters, freshly squeezed lime, and grapefruit juice.

Stir vigorously with a long-handled bar spoon for 30 seconds—strain into a chilled coupe-styled glass.

Top with a thin slice of lime and a single pink rose petal as a garnish.