Horticulturist Rudolph Boysen created this hybrid berry in 1923 by crossing a raspberry, blackberry and loganberry. It's shaped like a large raspberry, has a purple-red hue and a rich sweet-tart flavor. Choose boysenberries that are firm and uniform in size. Discard shrivelled or mouldy berries. Do not wash until ready to use, and store (preferably in a single layer) in a moistureproof container in the refrigerator for 2 to 3 days.