First, pour the yogurt into a bowl. Then add the cream. With a whisk carefully stir until combined. It should be nice and thick.
Sprinkle the brown sugar evenly over the top of the yogurt mixture. Do not stir the mixture. Cover the bowl with foil or plastic wrap and tightly seal the edges. Place in the refrigerator for at least three or four hours.
When you are ready to serve, place a small handful of berries (or other fruit) into a bowl or cup. Now, you can either not stir the mixture and have small visible bits of brown sugar in the finished product or you can whisk the mixture until smooth.