How to Make It
Preheat grill to high (450°F to 550°F). Layer 2 medium sheets of heavy-duty aluminum foil. Toss together raspberries and sugar on foil. Slide foil onto grill grate, and grill, uncovered, stirring once or twice, until juicy, about 8 minutes. Transfer raspberries and any juices to a blender, and let cool completely. Add lemon juice and a pinch of flaky sea salt; puree until very smooth. Transfer raspberry sauce to an airtight container, and refrigerate until chilled, about 30 minutes.
Meanwhile, grill peach wedges and pineapple slices, uncovered, until lightly charred, 3 to 4 minutes per side. Transfer to a work surface; let cool completely. Dice pineapple.
Decoratively layer ice cream, pineapples, peaches, and raspberry sauce in each of 6 (8-ounce) glasses. Sprinkle with flaky sea salt, and serve immediately.