Cut the stone fruits in half and remove the pits. Keep the skin on to help the fruit maintain its shape on the grill.
In a small bowl, combine the melted butter, brown sugar, 1 tablespoon honey, vanilla extract, cinnamon, and salt. Whisk until thoroughly combined.
Preheat your grill to medium heat (approximately 350-375°F). Clean and oil the grates to prevent sticking.
Brush the cut sides of the fruit with the glaze mixture. Place the fruit cut-side down on the grill.
Grill undisturbed for 4-5 minutes until grill marks appear and the edges begin to caramelize. Flip and cook for another 3-4 minutes until tender but not mushy.
While the fruit grills, beat the mascarpone cheese in a medium bowl until smooth. In a separate bowl, whip the heavy cream until soft peaks form.
Gently fold the whipped cream into the mascarpone, then add remaining honey to taste. Refrigerate until ready to serve.
Serve the grilled fruit warm, topped with a generous dollop of the chilled whipped mascarpone. Drizzle with extra honey and sprinkle with chopped nuts and fresh mint leaves.