Sugar, heat, and patience

Yes, you want high heat and some sugar on the surface. Caramelization is just heat breaking down sugars, so you have to give it something to work with.

Pineapple is the easiest fruit to grill because it’s already loaded with sugar. Just slice it into rings or spears, pat it dry (wet fruit steams, doesn’t caramelize), and hit a hot grill — 450°F or so. No oil needed if your grates are clean, but a light brushing of neutral oil helps with marks and sticking. Don’t move the pieces around. Let them sit 3-4 minutes per side until you see deep brown char marks.

Peaches are trickier because they have a lot of water. Halve them, remove the pit, and brush the cut side with a little oil and a sprinkle of sugar (turbinado or brown works well). You want the grill screaming hot. Place cut side down first and leave it alone until you see the caramelized lines. Flip once to warm the skin side briefly — no need to grill that side long. The flesh softens fast, so don’t overcook.

Other tips: keep the pieces big enough to handle, clean your grill grates well beforehand, and don’t bother with complicated marinades. A pinch of salt or a squeeze of lime after grilling adds more than any glaze ever will.

Stay away from low heat. You’ll just get mush.