This is such a deceptively delicious dessert. Traditionally, it is made with red currants as the star but few people have access to those tart gems unless they grow it, themselves. So now, for ease of preparation, this is made two ways: either with raspberries to add the characteristic tartness of the original version or with a mix of Summer berries such as raspberries, blueberries and strawberries. I'm made it every which way: traditional and modern and it's a hit every single time. Potato flour is the preferred choice of thickener; it can be purchased in the Jewish Foods aisle of your store if it's not in the baking aisle. Otherwise, ordinary corn starch can be substituted for the potato starch. I serve this in clear glass ramekins to enjoy the jewel-like tones and a thin layer of poured whipping cream is floated over the top. After a heavy meal or when it's scorching hot outside, this is the PERFECT simple dessert for your friends and family to enjoy. NOTE I: A different recipe, using the same ratios, is made with Rhubarb. NOTE II: Depending upon how you were taught to make this, after the fruit is softened through simmering, some families strain the berries to remove seeds and skins while others don't. It's delicious either way.