Preheat your oven to a cozy 350°F (175°C). Line a large baking sheet with parchment paper for easy cleanup.
In a medium bowl, gently whisk together your dry ingredients: flour, cornstarch, baking soda, salt, and cinnamon. Set this fragrant mix aside.
In the bowl of a stand mixer (or using a hand mixer), combine the softened butter, cream cheese, light brown sugar, and confectioners' sugar. Beat on high for 2-3 minutes until the mixture is wonderfully light and fluffy, scraping down the sides as needed to ensure everything is well combined.
With the mixer on low speed, slowly add in the egg and vanilla extract. Beat for about 1 minute until just incorporated.
Gradually add the dry flour mixture to the wet ingredients on low speed. Mix just until the ingredients are combined – be careful not to overmix, as this keeps your cookies tender!
Remove the bowl from the mixer. Gently fold in the white chocolate chips and half of your finely crushed Cinnamon Toast Crunch cereal. This adds a delightful surprise crunch inside!
Using a 3-tablespoon cookie scoop, drop rounded portions of dough onto your prepared baking sheet, leaving about 2 inches between each cookie.
Lightly flatten each cookie with the bottom of a kitchen glass. Then, generously sprinkle the remaining half of the crushed Cinnamon Toast Crunch cereal on top of each flattened cookie for an extra festive crunch.
Bake for 8-10 minutes. For the most wonderfully soft and chewy cookies, remove them from the oven when the edges are just barely golden and the centers look slightly set but still a little soft. Let them cool on the baking sheet for a few minutes before transferring to a wire rack.