To prepare the Cornmeal Pastry: In a medium bowl, stir together flour, cornmeal, and salt. Using a pastry blender, cut in butter, cut up, until pea size. Add canola oil; stir lightly with a fork until combined. Sprinkle 1 tablespoon cold water over part of the flour mixture; toss gently with fork. Push moistened pastry to side of bowl. Repeat moistening flour mixture, gradually adding cold water (3 to 4 tablespoons total) until mixture begins to come together. Gather pastry into a ball, kneading gently just until it holds together.