01 -  Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper, leaving an overhang for easy removal. 
 02 -  In a large bowl, whisk together melted butter and brown sugar until smooth. Add eggs and vanilla extract; whisk until fully combined. 
 03 -  In a separate bowl, sift together all-purpose flour, baking powder, and salt. 
 04 -  Gradually fold the dry ingredients into the wet mixture until just combined. 
 05 -  Gently fold in 1 1/2 cups crushed Cinnamon Toast Crunch and white chocolate chips, if using. 
 06 -  Spread the batter evenly into the prepared pan. 
 07 -  In a small bowl, mix granulated sugar and ground cinnamon. Sprinkle evenly over the top of the batter. Scatter the remaining 1/2 cup crushed cereal on top and lightly press it into the batter. 
 08 -  Bake for 28 to 32 minutes, or until the edges are golden and the center is just set. Do not overbake. 
 09 -  Allow to cool completely in the pan. Lift out using the parchment overhang, slice into squares, and serve.