• Freshly grated zest from 1 lemon
To prepare dough: In a medium bowl, whisk together flour, cornmeal, salt and sugar. Using a pastry cutter, cut cold butter into flour mixture until it resembles coarse crumbs (alternately, combine ingredients in a food processor fitted with a metal blade, and pulse). Add ice water, 1 tablespoon at a time, until mixture just comes together. Turn dough out onto a clean work surface and flatten into a disk. Wrap dough in plastic wrap and refrigerate at least 1 hour or up to 1 day (dough can be frozen for up to 1 month; thaw in refrigerator before rolling).
When ready to bake, preheat oven to 375 degrees and line a rimmed baking sheet with parchment paper. Remove dough from refrigerator and let it warm up slightly. On a lightly floured work surface, using a lightly floured rolling pin, roll dough out to a 12-inch round, about 1/8-inch thick. Transfer dough to prepared baking sheet and refrigerate until ready to add filling.