Spoon teaspoon-sized dollops of the peanut butter onto a wax paper-lined plate. Freeze until solid, about 30 minutes.

Preheat oven to 350°F. Spray a 10-inch cast iron skillet with nonstick cooking spray.

In a medium bowl, whisk the flour, cornstarch, baking soda, and salt together until combined; set aside.

In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and both sugars together on high until fluffy, about 2 minutes. Add the eggs, one at a time, followed by the vanilla, scraping the sides of the bowl if necessary.

Add the flour mixture, mixing until just combined. Stir in the white chocolate chips. Press half of the dough into the skillet. Press half of the candy corn into the cookie dough. Place the frozen dollops of peanut butter evenly over the dough. Cover with the remaining dough by pressing portions of dough between your palms, then piecing them together on top of the peanut butter. Make sure all of the peanut butter is covered. Top with remaining candy corn.

Bake for 25-30 minutes, or until the edges are lightly golden and the center looks glossy and not quite done. Pizookie will continue to bake as it cools. Wait 15 minutes before serving. Top with a scoop of vanilla ice cream, and enjoy!