Method

​1 Grease a 3 pint (1.7 litre) pudding basin (Pyrex bowl).

2 Prepare the topping first by melting the chocolate in a glass bowl over a saucepan of simmering water. Remove from the heat and stir in the sugar, cream and walnuts. Place in the base of the pudding basin (it will become the topping when you turn it over to serve).

3 To make the sponge: in a large bowl, cream the margarine with the sugar in a mixing bowl using an electric hand whisk. Beat in the eggs one at a time so it doesn't curdle and then fold in the sieved gluten-free flour and cocoa. Slowly spoon the sponge mixture on top of melted chocolate topping already in the pudding basin.

4 Cover the pudding by placing a circle of greaseproof paper over the bowl, making a pleat in the paper to allow the pudding to expand. Tie it on tightly with string or an elastic band. Then add a circle of foil, also with a pleat and again tie it on securely. Personally, I use elastic bands to secure them.

5 Steam the pudding for 1 ½ - 2 hours. Turn onto a warmed plate, and serve with custard or cream. See below for my guide to steaming.

Use either a steamer, which is a perforated pan that sits over another pan holding boiling water. Place the Pyrex bowl in the perforated pan and put on a tight fitting lid. Alternatively, use a very large saucepan with a tight lid and this is perfectly adequate. Here the Pyrex bowl is actually in the boiling water and so the base of the Pyrex bowl needs to be kept off the base of the pan. To do this, make a trivet of metal knives or forks placed cross-wise at the bottom of the pan, or place a saucer or soup plate upside down with the pudding basin on top. Pour in the boiling water to come halfway up the sides of the pudding basin.