Gently muddle the mint leaves, lime juice, and simple syrup in a Collins glass.
2.
Add the scotch and fill the glass with crushed ice.
3.
Float Campari on top and fill with more crushed ice.
4.
Garnish with a flaming lime shell (see notes).
Notes
To flame a lime shell: Squeeze the juice from half a lime, reserving the juice. Place the lime shell atop the prepared cocktail; place 1 sugar cube inside. Douse the sugar cube with 151-proof rum and carefully light on fire. Extinguish before drinking (or not).