Place a paper coffee filter in a small strainer or filter holder set over a cup or bowl. Spoon the yogurt into the filter and let drain, refrigerated, for one hour (or more). This will drain out some of the liquid for a richer and more creamy dip. The longer you drain, the thicker the yogurt becomes. (You can omit this step if you're in a hurry -- the dip won't be quite so thick but will still taste delicious.)
Dump drained yogurt into a small bowl. Add the brown sugar and vanilla, stirring until the sugar is dissolved.
Serve with desired fruit.
