Fudgy Brownies with Cornflake Toffee

This decadent caramel crunch brownie recipe transforms simple ingredients into an irresistible dessert that combines fudgy chocolate with a crunchy, caramel-coated cornflake topping. The contrast between the rich brownie base and the sweet, crispy topping creates a texture experience that will have everyone reaching for seconds.

I first created these brownies for a bake sale fundraiser, and they sold out within minutes. Now they're requested at every family gathering, and I've had to start making double batches because people always want to take some home.

Ingredients

• Brown sugar: Provides a deep molasses flavor that enhances the chocolate richness
• Caster sugar: Gives the perfect sweetness balance and helps create that crackly brownie top
• Salted butter: Adds richness and a subtle flavor enhancement
• Dark cooking chocolate: Forms the backbone of that intense chocolate flavor (choose 60 to 70% cocoa solids for best results)
• Large eggs: At room temperature incorporate better and create proper structure
• Extra egg yolk: Contributes to that perfect fudgy texture without making brownies too cake-like
• All-purpose flour: Just enough to provide structure without making brownies dry
• Cocoa powder: Intensifies the chocolate flavor (look for Dutch-processed for deeper color and taste)
• Vanilla extract: Enhances all the other flavors (always use pure extract, not imitation)
• Granulated sugar: Caramelizes beautifully for that amber toffee base
• Heavy cream: Ensures a smooth, velvety caramel consistency (use full-fat for best results)
• Cornflakes: Provide the signature crunch (look for fresh, crisp flakes for best texture)

Step-by-Step Instructions

Create The Fudgy Base:

Preheat your oven to 350°F with the rack in the middle position. The proper temperature is crucial for developing that perfect crackly top while maintaining a fudgy center. Line your baking pan meticulously with parchment paper, leaving overhang on all sides. This preparation step seems simple but makes removal and cutting infinitely easier later. If your parchment keeps curling up, use binder clips to secure it to the pan edges.

Melt Chocolate Mixture:

Combine brown sugar, white sugar, butter and chopped chocolate in a large microwave-safe bowl. Heat in 30-second intervals, stirring thoroughly between each until completely smooth. This gradual heating prevents the chocolate from seizing or burning. The mixture should be warm but not hot when done. If you prefer, you can use a double boiler method for more controlled melting.

Develop The Brownie Batter:

Add eggs and extra yolk to the chocolate mixture while it's still warm enough to create a slight sheen but not hot enough to cook the eggs. Whisk vigorously until fully incorporated, about 1 minute. The mixture should become slightly thicker and glossier. Then add flour, sifted cocoa powder, and vanilla. Fold gently until just combined, being careful not to overmix, which would develop gluten and make the brownies tough.

Bake To Perfection:

Pour the batter into your prepared pan, using a spatula to spread it evenly into the corners. Bake for 25-30 minutes until the edges are set but the center still has slight movement when the pan is gently shaken. A toothpick inserted will come out with a few moist crumbs, not wet batter. Allow to cool completely to room temperature before proceeding with the topping. This cooling period is essential for structural integrity.

Create Caramel Magic:

For the cornflake layer, place granulated sugar in a heavy-bottomed, light-colored saucepan over medium-low heat. This slow cooking is critical for proper caramelization. The light-colored pan helps you monitor the color changes accurately. Stir gently and infrequently with a wooden spoon just until sugar begins to melt, then stop stirring and let it cook undisturbed until it reaches a deep amber color or 245°F on a candy thermometer. Be vigilant during this process as sugar can go from perfect to burnt in seconds.

Develop Rich Toffee:

Once your caramel reaches the proper color, carefully add the hot cream in a slow, steady stream while stirring constantly. The mixture will bubble vigorously, so use caution. Add butter pieces gradually, continuing to stir until completely incorporated. Then bring back to a boil and cook for exactly 5 minutes or until it reaches 250°F. This precise temperature ensures your caramel will set properly when cooled but remain chewy rather than hard.

Finish With Crunch:

Working quickly, remove the caramel from heat and add cornflakes. Fold gently but thoroughly with a wooden spoon, ensuring every flake gets coated while trying not to crush them. Pour this mixture immediately over your cooled brownie base and spread into an even layer. Allow to cool at room temperature for 30 minutes before refrigerating for at least 2 hours to fully set.

Slice With Precision:

For clean, professional-looking squares, fill a tall container with hot water. Dip a sharp chef's knife into the water, wipe dry, then make a clean cut. Repeat the heating and drying process between each cut. For best results, cut straight down rather than using a sawing motion. This prevents the caramel cornflake layer from shattering or pulling away from the brownie base.

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The dark chocolate is truly the star ingredient in this recipe. I discovered through multiple tests that using chocolate with 65-70% cocoa solids creates the most balanced flavor profile. One memorable Christmas, I made these for a neighborhood cookie exchange and ended up having to share the recipe with 15 different families by New Year's.

Storage Success

These brownies keep beautifully in an airtight container for up to 5 days at room temperature or 7 days refrigerated. The caramel cornflake layer does soften slightly over time, but many people prefer this texture. For longer storage, you can freeze the cut brownies by wrapping individual pieces in plastic wrap then aluminum foil for up to 3 months. Thaw overnight in the refrigerator for best results.

Brilliant Variations

The base recipe is perfection, but you can create exciting variations with simple substitutions. Try using Frosted Flakes instead of plain cornflakes for an even sweeter topping. For a salty-sweet combination, fold 1/2 cup of chopped pretzels into the caramel along with the cornflakes. Coffee lovers can add 1 tablespoon of espresso powder to the brownie batter for a mocha version that pairs beautifully with the caramel topping.

Serving Suggestions

While these brownies are spectacular on their own, they reach new heights when served slightly warm with a scoop of vanilla ice cream. The contrast between the warm, fudgy brownie, crunchy caramel topping, and cold, creamy ice cream creates a sensory experience worth savoring. For an elegant dessert presentation, place a brownie square on a plate, add ice cream, and drizzle with additional warm caramel sauce.

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These brownies are the perfect balance of rich fudgy texture and crunchy caramel goodness—ideal for impressing guests or treating yourself. Enjoy every bite!

Frequently Asked Questions

→ Can I use milk chocolate instead of dark chocolate for the brownies?

Yes, you can substitute milk chocolate, but this will make the brownies significantly sweeter and less rich. If using milk chocolate, consider reducing the sugar in the brownie base by about 25% to compensate for the added sweetness.

→ Why do I need to heat the cream before adding it to the caramel?

Hot cream is essential when making the cornflake layer because adding cold cream to hot sugar can cause the caramel to seize and become grainy. The temperature difference would also create dangerous splatter. Always heat your cream before adding it to the hot sugar mixture.

→ Can I make these brownies in advance?

Absolutely! These brownies actually benefit from being made ahead. They can be stored in an airtight container in the refrigerator for up to 5 days. The cornflake topping maintains its crunch even after refrigeration.

→ What if I don't have a candy thermometer for the caramel?

While a candy thermometer gives the most precise results, you can use the cold water test method. Drop a small amount of the caramel into cold water - for the correct stage (soft ball), it should form a ball that flattens when removed from the water. The caramel should also be a deep amber color.

→ Why did my cornflake layer turn out too hard?

If your cornflake layer is too hard to bite through, the caramel was likely cooked to too high a temperature. Next time, cook the caramel to a slightly lower temperature or for less time. You can also try adding an extra tablespoon of butter to soften the final texture.

→ Can I freeze these brownies?

Yes, these brownies freeze well. Cut them into squares first, then place them in a single layer in an airtight container with parchment paper between layers. Freeze for up to 3 months. Thaw in the refrigerator overnight before serving.