Latticed Blackberry-Lime Pie

It was the Blackberry Pie recipe from What a Cook Ought to Know about Corn Starch (1909) that inspired mine. I love the bare-bones filling instructions: “Wash blackberries, drain and fill plate quite full. Sprinkle well with sugar. Sift over all, one generous tablespoon...[cornstarch].” Done and done. I added lime juice and zest (for a little zing), a bit of butter atop my filling (for richness), and arrowroot powder instead of cornstarch (for a less