How to Make It
Preheat oven to 425° F. Line a 9-inch pie plate or a 9-inch fluted tart tin with a removable bottom with the piecrust.
Spread the onions and olives over the dough. Top with the anchovies, if desired, and sprinkle with the Parmesan.
Bake until the crust is golden brown and crisp, 25 to 28 minutes.