This has never failed for me, despite years of various different unpredictable ovens, different shaped cooking vessels, etc.

SELF-SAUCING CHOCOLATE PUDDING from Aunty Jackie

Pudding:
1 C SR flour
¾ C sugar
1 Tbs cocoa
or 2 Tbs chocolate Quik
50g butter
½ C milk
1 tsp vanilla essence

Sauce:
¾ C brown sugar
1 Tbs cocoa / choc Quik
2 C hot water

Heat butter and milk gently, add vanilla and stir into dry ingredients. Pour into a deep oven-proof dish. Sprinkle on brown sugar and cocoa, and pour hot water over gently. Cook in a moderate oven (180 degrees C) 40 – 45 minutes.

Pour the water over the back of a spoon and make sure the spoon is almost touching the surface of the pudding, that way you won’t drill a hole in it. The pudding starts of with liquid on top and finishes with chocolate sauce underneath.