In a small bowl, mix together the mascarpone, cream and cinnamon with a rubber spatula. Set aside and let stand at room temperature while roasting the peaches.
Have ready a baking dish just large enough to hold the peach halves in a single layer. Butter the dish with 1 Tbs. of the melted butter. Place the peaches in the dish, cut side up, and brush the halves with the
remaining 1 Tbs. melted butter.
Bake until the peach juices collect in the hollows where the pits were removed, about 15 minutes. Remove from the oven. Brush the peaches with the honey, letting the juices run into the baking dish. Return to the oven and bake until the peaches are tender, about 5 minutes more. Serve the peaches immediately, with the cooking juices spooned on top, and top with the mascarpone and thyme. Serves 4 to 6.