Line a sheet tray with parchment paper for easy cleanup.

In a bowl, whisk together all-purpose flour, cornstarch, baking soda, baking powder, and fine sea salt.

In a large mixing bowl, beat softened unsalted butter and granulated sugar together until smooth. Add egg, creamy peanut butter, and vanilla extract. Mix until combined.

Gradually mix the dry ingredients into the butter mixture until just combined.

Add purple gel food coloring and mix until desired shade is achieved.

Scoop dough portions onto the prepared sheet and refrigerate for at least 2 hours.

Preheat oven to 350°F (175°C).

Roll each chilled ball in Halloween sprinkles before placing on another tray.

Bake for 9-11 minutes until cookies puff up and crack.

Cool for 5 minutes, then gently press a chocolate kiss on each cookie.