In a small pot, add one cubed mango, water and sugar.

Bring it to a boil over medium-high heat and once it reaches a boil, reduce the heat to low. Let the mango syrup simmer for 15-20 minutes allowing it to come together before removing it from the heat.

Strain the syrup into a heat proof glass and let it cool before using.

Transfer the syrup to a heat-proof jar and let it cool completely before using.

Store in the refrigerator for up to 2 weeks.  

To a shaker, add all of the ingredients (except the garnish) and shake until chilled, about 7-9 seconds.

Strain the cocktail into a chilled coupe glass and garnish with a fresh mango slice.