Place the water and sugar in a small saucepan and simmer until the sugar has dissolved.

Peel, quarter and core the quinces and place immediately into a mixture of water and lemon juice to prevent them from browning. Once they are all peeled, place in a baking dish and pour the sugar syrup over them.

Cover with foil and bake at 180°C until the quinces are completely soft and have changed colour from white to deep pink. This should take approximately 1 hour.

For the crumble, place the flour, sugar, oats and butter in a food processor and process until the mixture resembles breadcrumbs. Add the vanilla and briefly process again. Do not overwork the mixture.

Arrange the quinces in one large dish or 6 small individual bowls. Add the raspberries, sprinkle the crumble evenly over the top and pop back into the oven until the crumble is nicely browned.

Serve with warm vanilla custard or vanilla bean ice cream.