Slice pluots in half and remove the pit. Brush with honey syrup and place flesh-side-down on the grill over a medium flame.
Cook until pluots soften and start to caramelize (~5 minutes). Flip to skin-side-down and cook for another 3 minutes or so. Remove from heat and let cool.
To assemble the cocktail
Place two grilled pluots (four grilled pluot halves) into the bottom of a mixing glass.
Add the honey syrup and muddle, breaking apart the grilled pluots.
Add the Meyer lemon juice, aged balsamic, Hangar 1 Straight Vodka, and shake for 10 seconds.
Double strain over new ice into a highball glass and top with sparkling water. Garnish with a few fresh slices of pluot and serve!