Preheat the grill: Heat to medium (about 375–400°F). Clean and oil the grates to prevent sticking.
Prep the peaches: Brush cut sides with oil.
Sprinkle with brown sugar and a tiny pinch of salt to boost flavor.
Make the mascarpone: In a bowl, stir mascarpone with maple syrup, vanilla, lemon zest, and a pinch of salt until smooth. Adjust sweetness to taste, then chill.
Toast the pecans: In a small skillet over medium heat, melt butter. Add pecans, brown sugar, cinnamon, and salt.
Cook 2–3 minutes, stirring, until glossy and fragrant. Set aside to cool and crisp.
Grill the peaches: Place peaches cut side down. Grill 3–5 minutes until grill marks appear and the sugar caramelizes.
Flip and grill 2–3 more minutes until tender but not mushy.
Plate: Set peaches cut side up. Add a generous spoonful of maple mascarpone to each half. Sprinkle with pecan crunch.
Finish with mint or a light drizzle of maple syrup if you like.
Serve warm: These shine when the peaches are warm and the topping is cool.