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–+ servings
Close-up of caramel cornflake brownie layers.

Caramel Crunch Cornflake Brownies Recipe

Course: Bars, Dessert
Cuisine: American
Prep Time: 15 minutes
Cook Time: 35 minutes
Cooling Time: 1 hour
Total Time: 1 hour 50 minutes
Servings: 9 squares
Calories: 517kcal
Author: Becky Hardin
Turn a simple boxed brownie mix into gooey brownies with a rich homemade caramel sauce and crunchy cornflake topping for a dessert that's as easy to make as it is impressive to serve!
Print Recipe

Equipment

  • 9x9-inch Baking Pan

Ingredients

  • 18 ounces brownie mix plus eggs, water, oil*
  • 1 cup granulated sugar
  • ½ cup unsalted butter 1 stick; cubed, room temperature
  • ½ cup heavy whipping cream room temperature**
  • 1 teaspoon pure vanilla extract
  • ½ teaspoon kosher salt
  • 4 cups cornflakes cereal ***

Instructions

  • Preheat your oven according to the directions on your brownie package (usually 325°F or 350°F). Line a 9x9-inch square baking pan with parchment paper, leaving an overhang on the sides for easy removal later.
    Ingredients for caramel cornflake brownies, featuring boxed brownie mix, granulated sugar, heavy whipping cream, unsalted butter, cornflakes, vanilla, and salt.
  • Prepare the brownie mix in a medium bowl according to the package instructions, using the required eggs, oil, and water.
    18 ounces brownie mix
    Brownie batter in a mixing bowl.
  • Pour the batter evenly into your prepared 9x9-inch pan.
    Brownie batter spread into a 9x9 baking dish.
  • Bake the brownies according to the box directions, minus 2 to 3 minutes. Remove from the oven and let cool slightly in the pan.
    Brownies in a baking dish fresh out of the oven.
    • The brownies should be fully baked, with a slight gooey texture, but no runny batter in the center.
  • While the brownies bake, make the scratch caramel. In a large, heavy-bottomed saucepan over medium heat, add the granulated sugar in an even layer.
    1 cup granulated sugar
    Sugar melting in a pot.
  • Allow the sugar to melt slowly without stirring; but you can gently swirl the pan occasionally to ensure even melting. Cook the sugar until it transforms into a deep, translucent amber color.
    Caramelized sugar in a pot.
  • Immediately turn the heat down to low, and carefully drop in the cubed, room-temperature butter. Whisk vigorously until the butter is completely melted and integrated.
    ½ cup unsalted butter
    Adding butter to caramel sauce in a pot.
    • The mixture may bubble up intensely here, so use caution.
  • Slowly drizzle in the room-temperature heavy whipping cream, whisking continuously until a smooth, glossy caramel sauce forms. Let it simmer for exactly 1 minute on low heat to thicken.
    ½ cup heavy whipping cream
    Caramel sauce in a pot.
  • Remove the saucepan from the heat. Whisk in the vanilla extract and salt.
    1 teaspoon pure vanilla extract, ½ teaspoon kosher salt
  • Add the 4 cups of cornflakes directly into the hot caramel sauce. Using a flexible silicone spatula, gently fold the cornflakes into the caramel until the cornflakes are entirely coated.
    4 cups cornflakes cereal
    Cornflakes coated in caramel sauce.
    • Fold gently, instead of stirring aggressively, to prevent breaking or crushing up the cereal.
  • Spoon the hot caramel cornflake mixture evenly over the top of the baked brownies in the pan. Use the back of your spatula to press the flakes down very gently into a flat, uniform layer so they adhere firmly to the brownie base.
    Caramel cornflake brownies in a baking dish.
  • Allow the brownies to cool completely at room temperature for at least 1 hour; or pop them in the refrigerator for 30 minutes until the caramel sets. Lift the brownies out using the parchment paper handles, slice into 9 squares with a warm knife, and serve.
    A spatula lifting a caramel cornflake brownie with layers of fudgy brownie, sweet caramel, and crunchy cornflakes.

Notes

*Any standard fudge, milk chocolate, or dark chocolate box mix works here; or swap it for your favorite scratch brownie recipe. Be sure to get any ingredients called for on the back of the box, including eggs and oil.
**I do not recommend substituting the heavy cream for half n' half or any other ingredient. The high fat content of heavy cream is essential for a stable caramel sauce.
***Swap with Frosted Flakes if you prefer an ultra-sweet treat; or Rice Krispies / crispy rice cereal for a lighter, crackly-crunch texture akin to a crunch bar.
Becky's Top Tips:
  • Make sure your heavy cream and butter are fully at room temperature before adding them to the melted sugar, as cold dairy can cause the mixture to seize.
  • Line your 9x9-inch pan with parchment paper handles. Since caramel is super sticky, lifting the whole block out using the paper overhang makes it so much easier to cut perfect squares without fighting a high-sided pan.
  • When folding cornflakes into the hot caramel, keep them as whole as possible. You want a rustic, craggy texture on top rather than a dense paste, and those large flakes give you the ultimate crunch against the fudgy chocolate beneath.
  • Don't over-bake your brownie base. Boxed brownies keep cooking from residual heat, so pulling them out slightly underdone ensures the caramel topping melds into a perfectly gooey, fudgy layer.
Storage: Store your cut cornflake brownies in an airtight container at room temperature for up to 4 days.

Nutrition

Calories: 517kcal | Carbohydrates: 77g | Protein: 4g | Fat: 22g | Saturated Fat: 11g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 7g | Trans Fat: 0.4g | Cholesterol: 42mg | Sodium: 391mg | Potassium: 38mg | Fiber: 0.4g | Sugar: 52g | Vitamin A: 732IU | Vitamin C: 3mg | Calcium: 13mg | Iron: 5mg