Pour the granulated sugar on a plate.
Swipe the rim of the glasses with a lime wedge and dip the rim in the granulated sugar. Set aside.
Preheat your broiler.
Slice the grapefruit in half and dip the cut side into the granulated sugar until coated. Place them cut side up on a broiler proof pan and broil for a few minutes until the sugar caramelizes on top.
Remove the grapefruit from the broiler and allow to cool.
Using a citrus reamer juice the grapefruit into a bowl. Strain into a cup and set aside.
Add a lime wedge, 1 tablespoon of agave or honey and 2 tablespoons of mint leaves to each glass. Using a cocktail muddler or the end of a wooden spoon, muddle together well until the lime is crushed.
Pour one shot of rum or vodka in each glass and add the grapefruit slice. Fill the glass with the ice.
Divide the grapefruit juice between the two glasses and top it off with a splash of the sparkling water.
Garnish with one slice of lime, a slice of chili, a sprig of mint and lavender or basil blossoms. Enjoy !