Method
 

1. Break half the dark chocolate into a bowl; melt then cool; reserve the remainder for the top.

2. Cream the butter and sugar together, slowly add the beaten eggs with a little flour then fold in all the dry ingredients with the finely grated orange rind. If the mixture is too stiff, add a little orange juice.

3. Spoon half the mixture into a bowl with the melted dark chocolate and stir the chopped white chocolate into the other half. Space spoons of white mixture in the tin with the chocolate mixture in between and smooth the top very gently.

3 and 5 Oven AGA

4. Bake toward the bottom half of the Baking Oven for about 35 minutes until cooked through, protect with the cold plain shelf if necessary.

5. Cool a little in the tin before turning out.

6. Return the cake to the clean tin.

7. Dissolve the sugar in 4 tablespoons of water and when the sugar granules have disappeared, bring the syrup to boil for 3 or 4 minutes until slightly thicker, add any remaining orange juice from making the cake.

8. Cool before adding the orange liqueur then pour over the cake in the tin.

9. Later, lift the cake onto a pretty plate. Lightly whip the creams together then swirl over the top of the marble cake and decorate with chocolate curls or grated chocolate.

Conventional cooking
Bake in a moderately hot oven 190°C (375°F) Gas Mark 5 for about 35 minutes until cooked in the centre.