Preheat your oven to 350°F (175°C).
Line a baking sheet with parchment paper and set it aside.
Place the cornflakes in a large mixing bowl.
In a heavy-bottomed saucepan over medium heat, combine the butter and brown sugar.
Cook for about 2 minutes until the butter is melted and the mixture begins to simmer.
Allow the mixture to bubble for an additional 2 minutes.
Quickly pour the hot mixture over the cornflakes.
Stir until all the cornflakes are well coated.
Spread the coated cornflakes evenly on the prepared baking sheet.
Bake for 12-15 minutes, or until lightly golden brown.
In a microwave-safe bowl, melt the chocolate almond bark in 30-second intervals until smooth.
Spread the melted chocolate over the brittle.
In another microwave-safe bowl, melt the red candy melts in 30-second intervals until smooth.
Repeat the process with the green candy melts.
Drizzle the melted red and green candy over the brittle and gently swirl with a knife.
If desired, add sprinkles on top.
Allow the brittle to cool completely before breaking it into pieces.
Serve and enjoy!