Cream the butter and peanut butter together.
Add the icing sugar and vanilla and blend thoroughly.
Shape into small 1-inch balls.  Refrigerate on waxed paper for half an hour.

Melt the white chocolate (you can use a microwave for this).
With a toothpick, dip the "eyeballs" into the chocolate, covering all but a small circle on the top.

Let cool on waxed paper. Makes around 40 eyeballs.