Preheat grill to 450 degrees.
Place pineapple slices on preheated grill. Grill both sides 3-4 minutes each or until nicely browned. Remove from grill and cool.
In JoyJolt Highball glasses, add ice or frozen pineapple chunks to glass.
Top ice with seltzer water.
Add 2-3 tablespoons of Torani syrup to each glass. Stir to combine.
Top with a grilled pineapple slice. Enjoy!