Preheat oven to 180°C.

Grease a 2-litre pudding dish with unsalted butter.

Place sugar in a saucepan over low heat and cook to a golden caramel.

Remove from the heat and whisk in quince poaching liquid, then pour into pudding dish. Scatter with sliced quince.

For sponge, place butter and sugar in bowl of an electric mixer and cream together for 2-3 minutes.

With mixer still going, add eggs, 1 at a time.

Sieve flour, baking powder and salt together and hand-fold into egg mix using a spatula.

Pour sponge mix onto quinces in pudding dish, and cover tightly with foil.

Place dish in a roasting tray, then pour hot water into tray, so it comes half way up sides of the dish.

Steam-bake pudding for 2 hours or until cooked.

To test if sponge is ready, insert a metal cake skewer into the centre; if skewer comes out clean, pudding is cooked.

Remove foil, allow pudding to stand for 10 minutes, then carefully turn out.

Cut into thick slices and serve warm with crème fraîche.