Blackberry Frozen Yogurt

The basic frozen yogurt technique detailed here can be adapted to just about any fruit. (Obviously some fruit will need to be diced before it’s cooked, and some won’t need any straining to remove seeds.) My mom made it every July with black raspberries, and because it keeps so well—at least 6 months in the freezer—I always make plenty of it to enjoy any time I miss fresh berries. The egg whites add body and help keep the frozen yogurt soft enough to scoop out straight from the freezer—or wi