Can you use self raising flour instead of plain to make rock cakes?

No, it is not recommended to use self-raising flour instead of plain flour to make rock cakes.

Self-raising flour contains a raising agent, usually baking powder, which causes the flour to rise when mixed with liquid. Plain flour does not contain a raising agent, so the dough will not rise when mixed with liquid.

For rock cakes, you should use plain flour, sugar, butter, eggs, and a raising agent such as baking powder. If you use self-raising flour, the rock cakes will be too light and fluffy, and they will not have the traditional dense, crumbly texture.