Fresh ripe blackberries make a wonderful flavor for summertime ice cream that also has a lovely color, too. This recipe can be made without using any special tools or even any churning., just your freezer. What gives it that rich and airy consistency is both whipped cream and also beaten egg whites. Save some of the berries to use a garnish, if desired, and let the ice cream soften a bit at room temperature before scooping and serving.