First, pour the yogurt into a bowl. Then add the cream and vanilla. 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 20 to 30 minutes.
When you are ready to serve, place a small handful of berries (or other fruit) into a bowl or cup. Without stirring the mixture, spoon the yogurt over the berries. There will be creamy areas and brown sugar areas. Repeat the layers once, ending with berries on top.