Hi Charlene,
I don't normally recommend only recessed lighting in a bathroom. The reason being if someone is trying to put on makeup or shave in the mirror there are going to be shadows on your face. The best situation if possible is recessed lights and wall sconces. Since this is a powder room and perhaps doesn't get that kind of use, recessed lights may be fine. Two 5" cans is probably all you need. It's hard to do more because you will crowd the ceiling. Hope this helps.
Paul
Light is not so much something that reveals, as it is itself the revelation.
James Turrell