To make the cinnamon toast crunch 'flour' pulse 1 cup of the cereal in a food processor for about a minute. You'll want a relatively fine level of crumb. Set aside.
For the dough: In a medium or large mixing bowl, cream 8 tbsp of softened butter with the dark brown sugar (about 3 minutes). Add the egg and vanilla extract and mix for another minute or two until combined.
To the same dough bowl, add the flour, baking powder, salt and the ground cinnamon toast crunch. Mix until smooth and combined.
Using a spatula, fold in half of the cream cheese frosting into the batter. Cover and store in fridge, overnight ideally.
Once combined, refrigerate overnight (ideal).
Preheat oven to 350°. Line a sheet tray with parchment paper and using a teaspoon cookie scooper (or spoon), place cookies about 3 inches apart on tray.
Bake for roughly 11-12 minutes depending on your oven. Once they start to get a light golden brown edge, they're done.
Let cool and take the left over cream cheese frosting and place a dollop of it on each cooled cookie (using the back of a spoon works in this case if you don't have an offset spatula).
Place a couple of cinnamon toast crunch cereal bits on top of each cookie and enjoy! Cookies are best the same day of baking but can be stored in an airtight container for up to two days.