Brown the butter: In a saucepan over medium heat, melt the butter. Continue cooking, stirring often, until the butter foams and turns golden brown with a nutty aroma. Remove from heat and let cool for 10–15 minutes.

Mix wet ingredients: In a large mixing bowl, combine the brown butter, brown sugar, and granulated sugar. Mix until well combined. Add eggs and vanilla extract, and mix again until smooth.

Add dry ingredients: In a separate bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon. Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Fold in cereal and chips: Stir in the crushed Cinnamon Toast Crunch and white chocolate chips (if using).

Chill the dough: Cover and refrigerate the dough for at least 1 hour (or up to overnight).

Preheat oven to 350°F (175°C): Line baking sheets with parchment paper.

Scoop and bake: Scoop dough (about 2 tbsp per cookie) onto the prepared baking sheets, spacing them about 2 inches apart. Press a few extra cereal pieces on top for a crunchy finish.

Bake for 10–12 minutes, or until the edges are golden and the centers look slightly underbaked. They’ll continue cooking as they cool.

Cool on pan for 5 minutes, then transfer to a wire rack to cool completely.