I perfected my Caramel Toffee Crunch Cake, a recipe that hides a surprising twist in every slice and always leaves people guessing how I pulled it off.

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I thought I knew what indulgence was until I made this Caramel Toffee Crunch Cake. The moment a fork hits the tender crumb and you get that snap of crushed toffee bits, you sit up, it’s almost rude.

I used unsalted butter in the batter so the edges crisp up just enough and the crunch sings against the soft cake. It looks like something from a fancy shop yet it keeps secrets, the kind of thing I stash on my Desserts That Wow list.

You will want to hide it, or at least claim the biggest slice.

Ingredients

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All purpose flour: mostly carbs, low fiber, gives structure and tender crumb, not very nutritious.
Unsalted butter: rich in fat and vitamin A, makes cake moist and super flavorful.
Granulated sugar: pure carbs, adds sweetness and browning, little nutritional benefit.
Eggs: good protein, helps bind and leaven, adds richness and slightly savory note.
Whole milk: provides fat, calcium and protein, keeps crumb tender and milky tasting.
Sour cream or Greek yogurt: adds tang, moisture, some protein and a tender crumb.
Heavy cream: key for caramel, high fat for smooth texture and silky mouthfeel.
Toffee bits and chopped bars: crunchy sweet candy, mostly sugar and fat, adds texture.

Ingredient Quantities

For the cake: 2 1/2 cups all purpose flour

1 tbsp baking powder

1/2 tsp baking soda

1 tsp fine salt

1 cup (2 sticks) unsalted butter softened room temp

1 3/4 cups granulated sugar

4 large eggs room temp

1 tsp vanilla extract

1 cup whole milk room temp

1/2 cup sour cream or plain Greek yogurt

For the caramel sauce: 1 1/2 cups granulated sugar

6 tbsp unsalted butter, cubed

3/4 cup heavy cream, warmed

1 tbsp light corn syrup (optional)

1 tsp vanilla extract

1/2 tsp fine sea salt, plus more to taste

For the salted caramel buttercream: 1 cup (2 sticks) unsalted butter softened

3 to 4 cups powdered sugar sifted

1 cup cooled caramel sauce (reserved from above)

2 to 3 tbsp heavy cream or milk, as needed

1 tsp vanilla extract

1/4 to 1/2 tsp fine sea salt

For the toffee crunch and topping: 2 cups crushed toffee bits or about 10 to 12 Heath or Skor bars, chopped

1 cup chopped toasted pecans or almonds (optional)

Flaky sea salt for sprinkling (optional)

How to Make this

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1. Preheat oven to 350°F (177°C). Grease and flour two 9 inch round pans or line with parchment. Whisk together 2 1/2 cups all purpose flour, 1 tablespoon baking powder, 1/2 teaspoon baking soda and 1 teaspoon fine salt, set aside.

2. In a large bowl beat 1 cup (2 sticks) unsalted butter softened with 1 3/4 cups granulated sugar until light and fluffy, about 3 to 5 minutes. Add 4 large eggs one at a time, scraping the bowl between each, then stir in 1 teaspoon vanilla extract.

3. Add the dry ingredients to the butter mixture in three additions, alternating with 1 cup whole milk and 1/2 cup sour cream or plain Greek yogurt, beginning and ending with the dry mix. Mix until just combined, dont overmix or the cake will be dense.

4. Divide batter evenly between the prepared pans, smooth the tops and bake 25 to 30 minutes or until a toothpick comes out with a few moist crumbs. Cool in pans 10 minutes, then turn out onto a rack and cool completely.

5. Make the caramel sauce in a heavy bottom saucepan: heat 1 1/2 cups granulated sugar over medium heat, gently swirling the pan as it melts until it becomes a deep amber color, dont leave it or it will burn. Carefully add 6 tablespoons unsalted butter cubed and stir until melted, then slowly add 3/4 cup warmed heavy cream and 1 tablespoon light corn syrup if using, stirring until smooth. Remove from heat and stir in 1 teaspoon vanilla extract and 1/2 teaspoon fine sea salt. Let cool to room temperature, reserve 1 cup of this cooled caramel for the buttercream and keep the rest for drizzling.

6. Make the salted caramel buttercream: beat 1 cup (2 sticks) unsalted butter softened until fluffy. Gradually add 3 to 4 cups sifted powdered sugar, then beat in the 1 cup cooled reserved caramel sauce, 1 teaspoon vanilla extract and 1/4 to 1/2 teaspoon fine sea salt. Add 2 to 3 tablespoons heavy cream or milk as needed to reach a spreadable consistency, taste and adjust salt or sweetness.

7. Chop about 10 to 12 Heath or Skor bars to make roughly 2 cups crushed toffee bits and chop 1 cup toasted pecans or almonds if using. Reserve about 1/2 cup of the toffee mix for the top garnish.

8. Level the cake layers if needed. Place the first layer on a cake plate, brush lightly with some of the extra caramel sauce, spread a layer of buttercream, then sprinkle a generous layer of the toffee and nut mix pressing it lightly into the frosting.

9. Add the second layer, brush with more caramel, apply a thin crumb coat of buttercream and chill 20 minutes to set. Finish with a smooth final coat of buttercream, press the remaining toffee and nuts onto the sides and top, then drizzle more warm caramel over the top and sprinkle flaky sea salt to taste.

10. Chill the cake 30 minutes to let everything set, or chill longer for cleaner slices. For neat slices run a knife under hot water, dry it quickly and slice, wiping the blade between cuts. Serve at room temperature for best texture.

Equipment Needed

1. Oven (preheat to 350°F)
2. Two 9-inch round cake pans plus parchment paper or grease and flour them
3. Stand mixer or electric hand mixer (or a whisk if you wanna do it old school)
4. Mixing bowls (one large for batter, one medium for caramel/frosting)
5. Measuring cups and spoons (and a kitchen scale if you got one)
6. Sifter or fine mesh sieve for flour and powdered sugar
7. Heavy-bottomed saucepan and a heatproof spatula or wooden spoon for the caramel
8. Offset spatula or bench scraper and a serrated knife for leveling and smoothing the cake
9. Cooling rack, pastry brush and a baking sheet to catch drips and for brushing on extra caramel (dont skip the sheet)

FAQ

Q: Why did my cake turn out dense instead of light and tender? A: Most likely too much flour or overmixing. Spoon flour into the cup and level it, dont pack it. Use room temp butter, eggs and milk so they blend easily, fold batter just until combined, and make sure your baking powder is fresh.

Q: My caramel went grainy or seized, what do I do? A: Grainy caramel usually means sugar crystallized or the cream was too cold. Use a clean pan, melt sugar without stirring too much (swirl the pan), add a little corn syrup if you got it, and pour in warmed cream slowly. If it seizes you can try reheating gently and stirring, but sometimes you gotta start over.

Q: The buttercream is too thin or too thick, how do I fix it? A: If it’s too thin chill it for 15 minutes or add more sifted powdered sugar a little at a time. If it’s too stiff add 1 tsp at a time of cream until it loosens. Make sure the caramel you add is cooled so it doesnt melt the butter.

Q: How do I keep the toffee crunch from getting soggy on the cake? A: Wait to add the toffee until just before serving, or press the toffee into the buttercream right before guests arrive. Store toffee bits separate in an airtight container, and if using nuts, toast them first so they release less oil.

Q: Can I swap ingredients like sour cream or corn syrup? A: Yes, you can use plain Greek yogurt instead of sour cream at the same amount. Corn syrup in the caramel is optional but it helps prevent crystallization, you can skip it though, just watch the caramel closely.

Q: How should I store and reheat the cake? A: Store covered at room temp for 1 to 2 days, or refrigerate up to 4 days because of the buttercream and caramel. For longer keep, freeze wrapped tightly for up to 2 months. Thaw in the fridge overnight then bring to room temp before serving, a quick few seconds in the microwave on low for a slice helps loosen the caramel.

Caramel Toffee Crunch Cake Recipe Substitutions and Variations

All purpose flour: swap for cake flour for a lighter, more tender crumb. Either use 2 1/2 cups cake flour or make your own by removing 2 tbsp of flour per cup and replacing with 2 tbsp cornstarch (for 2 1/2 cups AP remove 5 tbsp flour, add 5 tbsp cornstarch).
Unsalted butter (cake and buttercream): if you only have salted butter, go ahead and use it, but omit the 1 tsp fine salt in the cake and cut the buttercream salt back (start with 1/4 tsp and taste). Salt levels vary so taste as you go.
Whole milk + sour cream: you can replace both with 1 1/2 cups buttermilk for a tangy, moist cake. If your buttermilk is very thick, thin it with a splash of milk. The acid in buttermilk helps the rise and texture.
Toffee bits / Heath or Skor bars: if you cant find them, substitute 2 cups chopped chocolate-covered toffee, or for a similar crunch-sweet combo use 1 1/2 cups toasted chopped pecans plus 1/2 cup chopped chocolate chips (gives texture and chocolate balance).

Pro Tips

– Get your room temp stuff really room temp, not just slightly warmed. If the butter is too soft the batter will be greasy, too cold and it wont cream properly. A quick trick: pop eggs in warm (not hot) water for 5 minutes, and if the butter dents when you press it but still holds shape it’s perfect.

– Measure flour correctly, don’t scoop with the cup. Spoon the flour into the measuring cup and level it off or even better use a scale. Overmeasuring makes a dry, dense cake, and overmixing after you add the flour makes it tough, so stop when just combined, leave a few streaks rather than beating it to death.

– With the caramel be patient and don’t rush it. Use a heavy pan, melt the sugar until a deep amber and swirl the pan, dont stir with a spoon or it can crystalize. When adding butter and warm cream add them slowly while whisking, and always use warm cream so the sauce doesnt seize. If it does seize a splash of warm water and steady heat usually brings it back.

– Chill between coats and temp control for the buttercream matters. Make sure the caramel is fully cooled before adding to the butter or the frosting will be too loose. Add powdered sugar slowly, whip the butter first, then incorporate caramel on low speed so it doesnt split. If the frosting gets too soft chill briefly, then whip again for a smooth finish.

– Keep texture in mind when assembling. Toast your nuts and chop the toffee coarsely for crunchy contrast, reserve some for the top. Brush layers lightly with warm (not hot) caramel, dont soak them or it will collapse. For clean slices dip a knife in hot water, dry it and slice, wiping the blade between cuts.