Peel and core the pears and cut into roughly 3cm cubes. Place into a saucepan with the dessert wine, water, vanilla, cardamom pods and raw sugar. Cook, stirring often for about 20 minutes or until pears are cooked. Remove from the heat and add the rosewater. Remove the cardamom pods and set aside.
To make the crumble, place the butter, flour, brown sugar, chopped pistachios, coconut and a pinch of salt into a bowl. Rub the mixture with your fingers until the butter has been incorporated and it forms a crumbly texture.
Place the pears into a baking dish and scatter the crumble mixture over the top. Bake for 20-30 minutes, until the topping is golden. Remove from the oven and lightly press the squares of white chocolate into the warm crumble topping. Serve warm with vanilla ice cream.