Font outline

Using the text UI element is it possible to outline the text in a different colour?

Have you added the Outline component?

I suggest you take a look at Text Mesh Pro which also works with Unity's new UI. It uses a different text rendering technique which makes your text elements look amazing with no performance impact. Adding a Stroke, Shadow, Bevel, Glow, etc comes down to simply changing material properties.

Here is a link to the asset store thread where you can see lots of examples and information about it.