Heat butter and golden syrup together until bubbling.
Reduce heat and stir in cream.
Add salt and cinnamon.
Cook until slightly thickened.
Place peaches cut-side down on the grid over medium coals or grill on a heated griddle pan. Cook until softened.
Stir vanilla essence and mascarpone together.
Serve grilled peaches with dollops of vanilla mascarpone and drizzles of caramel sauce.