Preheat oven to 350°F. Line a large baking sheet with parchment paper.
In a medium bowl, whisk together flour, cornstarch, baking soda, salt, and cinnamon until combined. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, add butter, cream cheese, and sugars. Beat on high for 2-3 minutes, or until ingredients are fully combined. Scrape down the sides of the bowl as needed.
With the mixer on low speed, add in the egg and vanilla and beat for about 1 minute.
With the mixer on low speed, slowly add the dry ingredients and continue to mix for about 1 minute, or until ingredients are just combined. Remove bowl from stand.
Fold in the white chocolate chips and half of the crushed Cinnamon Toast Crunch cereal.
Using a 3-tablespoon cookie scoop, scoop the dough out onto the prepared baking sheet about 2 inches apart.
Using the bottom of a kitchen glass, slightly flatten each cookie.
Use the remaining half of the crushed Cinnamon Toast Crunch cereal to top each cookie.
Bake for 8-10 minutes. The cookies are better when slightly underdone and just barely brown on the edges.