Preheat oven to 180°C.
Place peach halves into a bowl and cover with boiling water - soak for 45 seconds. Remove from the water and take off peach skins.
Mix the vino cotto, sugar and vanilla in a jug until the sugar has melted. Place the peaches into a shallow baking dish and cover with the liquid mixture. Be sure to spoon some of the liquid into the tops of the peaches where you removed the stone so it takes up the flavour.
To make the crumble topping, put the sugar, flour and butter into a mixing bowl and rub together until it resembles breadcrumbs. Add the granola and chopped nuts if using and mix with a spoon.
Top each peach half with a generous amount of the crumble. Don’t worry if some spills into the tray, it will soak up the lovely sauce which you can then use to dress your plate when serving.
Bake in the oven for 20-25 minutes. Check the dish occasionally to make sure the sauce isn’t catching. If it does, add a splash more vino cotto to loosen it again.
Remove from the oven and serve with a generous blob of clotted cream, drizzling the sauce over the crumble top.