Preheat oven to broil. Place all grapefruit halves cut side up on a baking sheet and sprinkle a small amount of maple sugar on top. Place in oven to cook for 5 minutes, or until the tops of the grapefruit have become golden.
While the grapefruit cooks, place water and maple sugar in a small saucepan over medium heat and cook until the sugar dissolves completely, about 4-5 minutes. Remove from heat.
Using a towel to grab each grapefruit half (make sure you do not burn yourself here), place each half on a citrus juicer to remove all the juice from the grapefruit. 5 grapefruit should give you 2 cups worth of juice. Strain the liquid through a fine mesh strainer and add the juice to the simple syrup and mix to combine. Place in fridge to cool completely.
Place crushed ice in a high ball glass, add a grapefruit slice, then a shot of gin, 2 shots of the simple syrup then top the rest off with tonic water! That’s it! Easy peasy!
Notes
*if you use coconut sugar, the drink will look much darker, just keep that in mind