For many years, my grandmother, Nanny, had a dozen or so large blackberry bushes thriving in her sunny backyard. Growing up, it was such a treat when the "season" opened as my sister and I would race out with a big bowl, eating and collecting from bush to bush. Those we didn't eat we brought inside to store or to dip in sugar and savor. Those we stored were most often turned into this pie, a sure hit and favorite of everyone I've ever made it for. The crust is a family tradition too and is both easy and superb. This freezes beautifully!