Spotted dog

Spotted dick is a traditional British steamed pudding, historically made with suet and dried fruit (usually currants or raisins) and often served with custard. Non-traditional variants include recipes that replace suet with other fats (such as butter), or that include eggs to make something similar to a sponge pudding or cake. Spotted is a reference to the dried fruit in the pudding (which resemble spots). The word dick refers to pudding. In late 19th century Huddersfield, for instance, a glossary of local terms stated: "Dick, plain pudding. If with treacle sauce, treacle dick." This sense of dick may be related to the word dough. In the variant name spotted dog, dog is a variant form of dough.

Source: Wikipedia