This candy bar layer cake features rich and moist Dutch chocolate cake layers baked on a sandy, buttery shortbread crust, filled with a thick salted toffee sauce, fudgy chocolate ganache, and hunks of Heath bar, all covered in the silkiest, most luscious milk chocolate Swiss meringue buttercream. The very best of a Twix and Heath bar turned into the ultimate candy bar-inspired cake of your dreams.
I’ve been dreaming up different versions a candy bar-inspired cake for about as long as I’ve been baking. Finally, I can present you with what I consider the ultimate combination of candy bar elements in the form of a rich chocolate layer cake.
Though I originally planned on adhering strictly to the flavors of Twix–shortbread cookie, thick caramel, and milk chocolate–eventually it hit me… What rule says I have to stick to the flavors of one candy bar? There are no rules. Thus, we have a mash-up of my favorites:
- crunchy shortbread cookie (think Twix)
- thick salted toffee sauce (I prefer the butterscotch flavor over traditional caramel)
- big hunks of Heath bar (actually my favorite candy bar!)
- rich chocolate ganache (like the coating of most of the classic chocolate candy bars)
- milk chocolate Swiss meringue buttercream (reminiscent of 3 Musketeers filling)
This also happened to be my choice for my 30th birthday cake, and it definitely delivered for a celebration.
I realize I obsess over every new cake recipe, but THIS ONE… This cake is indulgence in its highest form for me. My tried and true, ultra moist Dutch chocolate cake layers + plenty of crunch and cookie crumble + the nutty and buttery flavors of toffee and butterscotch + sweet-salty balance + fudge + cloud-like frosting = all of my dreams.
Dutch chocolate cake layers
It all starts with the chocolate cake. I keep coming back to this batter again and again for all my chocolate cakes, because honestly it doesn’t get any better than this. A few things make it special:
- Dutch cocoa: While cocoa is naturally acidic, Dutch cocoa is alkalinized, resulting in a smoother, deeper chocolatey flavor (think devil’s food cake). Look for any unsweetened cocoa “processed with alkali.”
- Buttermilk and sour cream: This combo gives the cake full flavor, excellent rise, super soft texture, and incredible moisture. Full fat preferred for both.
- Neutral oil (such as refined almond oil, vegetable oil, etc.): Helps the cake retain even more moisture compared to butter.
- Espresso: Enhances the chocolate flavor of the cake (without making it taste like coffee).
- Baking soda and baking powder: Extra baking soda (sodium bicarb) is important for the optimal reaction with acidic buttermilk and sour cream and the fluffiest result.
Shortbread crust
I have become a huge fan of baking cake layers on top of a crust! For me, some form of crunch component is almost always essential in the perfect layer cake. By baking it right in with the cakes as a crust, you can save yourself a step and conveniently get the perfect size and shape for the cake. It’s just a matter of timing to get the perfect bake on both the crust and the cakes, but so easy to do.
This crust is a buttery and crumbly shortbread cookie, a nod to the beloved Twix bar. It provides the perfect crunchy contrast and balance of flavor against the rich chocolate, while being thin enough not to take away from the overall soft and moist mouthfeel of the cake.
You just combine cold cubed butter, sugar, flour, and salt with a fork (no mixer or creaming or anything!), press the dough into the cake pans, and bake about 12 minutes before adding the cake batter.
Milk chocolate Swiss meringue buttercream
I know what you’re thinking–it seems so much easier to make a quick American buttercream with butter and powdered sugar. But go with me on this! Making meringue is actually very simple and doesn’t take a significant amount of extra time. When you eat the first spoonful of glossy, silky-smooth, not-too-sweet, bakery-worthy buttercream, you won’t have an ounce of regret.
It starts with egg whites and sugar whisked together over simmering water in a saucepan. The heat helps melt the sugar into the mixture as well as bring the egg whites to a safe temperature. After 3-4 minutes over heat, keep whipping at room temperature another 7-8 minutes, until you have stiff peaks and the bowl has completely cooled.
Tip: Avoid organic sugars because the crystals are usually too big to dissolve well, leaving you with a gritty texture. Refined granulated white sugar will give the best results.
Next, cubed unsalted butter (softened to barely cooler than room temp) is gradually mixed into the meringue. Expect it to look liquidy at first, then to quickly curdle into clumps. That’s ok! It’s supposed to happen. Keep mixing until you have a thick and creamy buttercream.
Finally, just mix in salt, vanilla, and melted/cooled semi-sweet chocolate, and you have the dreamiest smooth and fluffy milk chocolate buttercream that you can eat with a spoon.
Chocolate ganache
The chocolate ganache is a simple combination of hot heavy cream and good-quality semi-sweet chocolate. The ratio of about 1.7:1 (chocolate to cream by ounce) makes a fudgy ganache that’s perfect for a rich filling and is also pipeable for decorating.
Salted toffee sauce
Aka butterscotch sauce, aka pure magic. Right next to chocolate, toffee or butterscotch (essentially the same except for temperature/texture) is one of my favorite flavors. A thick salted caramel would also work wonderfully in this cake, but the toffee version just adds a little more depth with the help of brown sugar. It also happens to be easier to make. Just combine unsalted butter, brown sugar, salt, and heavy cream in a saucepan and simmer it down into a beautiful golden sauce, then stir in vanilla. It thickens as it cools, turning into the ultimate oozy cake filling.
Assembly
This recipe as written makes either a three-layer 6-inch cake or a two-layer 8-inch cake. *For the photos of this post, though, I scaled the recipe to 2/3 and made a two-layer 6-inch cake.
Start with the bottom cake layer, crust side down. Pipe a rim of buttercream around the perimeter to create a wall to contain the fillings.
Spread on a layer of ganache, then a thick coating of toffee sauce at room temperature. Place this in the fridge for several minutes to set before stacking any further.
Next comes a bonus layer of roughly chopped candy bar! I used Heath bar, my personal favorite.
Place the second cake layer on top, and repeat the fillings if making 3 layers.
After adding the final cake layer, place the cake back in the fridge for a few more minutes before frosting the outside. Start with a “crumb coat,” then chill and add your final coat of frosting. If desired, use extra ganache for piping or decorating.
Candy Bar Layer Cake
This candy bar layer cake features rich and moist Dutch chocolate cake layers baked on a sandy, buttery shortbread crust, filled with a thick salted toffee sauce, fudgy chocolate ganache, and hunks of Heath bar, all covered in the silkiest, most luscious milk chocolate Swiss meringue buttercream. The very best of a Twix and Heath bar turned into the ultimate candy bar-inspired cake of your dreams.
Notes
The recipe as written makes a three-layer 6-inch cake or a two-layer 8-inch cake.
Ingredients
For the shortbread cookie crust:
- 6 Tbsp unsalted butter, cold and cubed
- 3 Tbsp granulated sugar
- 112g (scant 1 cup) all-purpose flour
- 1/8 tsp salt
For the chocolate cake:
- 1 cup granulated sugar
- 1/3 cup neutral oil (such as refined almond oil or vegetable oil)
- 1/4 cup full-fat sour cream, room temperature
- 1/4 cup buttermilk, room temperature
- 1 large egg, room temperature
- 1 tsp vanilla extract
- 1 cup (120g) all-purpose flour, sifted
- 1/2 cup (48g) Dutch-process cocoa powder (unsweetened cocoa processed with alkali), sifted
- 1 tsp baking soda
- 1/2 tsp baking powder
- 1/2 tsp fine sea salt
- 1/2 cup boiling water
- 1/2 tsp instant espresso powder
For the salted toffee sauce:
- 4 Tbsp unsalted butter
- 1/2 cup brown sugar, packed
- 1/3 tsp fine sea salt (or up to 1 tsp large flakey sea salt)
- 1/2 cup heavy cream
- 1 tsp vanilla extract
For the ganache:
- 3 oz good quality semisweet chocolate chips or chopped chocolate
- 3.5 Tbsp heavy cream
For the chocolate Swiss meringue buttercream:
- 3 large egg whites
- 3/4 cup granulated sugar (refined, not organic)
- 1 cup unsalted butter, softened to just cooler than room temperature and sliced into 1-Tablespoon portions
- 5 oz high quality semi-sweet chocolate, melted cooled to room temperature
- 1 tsp vanilla extract or vanilla bean paste
- 1/16 to 1/8 tsp salt
For assembly:
- Large handful roughly chopped Heath bar (or your favorite candy bar)
Instructions
Make the crust:
- Preheat oven to 350. Prepare three 6-inch or two 8-inch round cake pans by spraying with nonstick spray or greasing with butter and lining the bottom with parchment paper, then greasing over the parchment paper.
- In a medium-sized mixing bowl, combine sugar, flour, and salt. Use forks or a pastry cutter to cut in the cold cubed butter until evenly combined and sandy.
- Divide mixture evenly into the prepared cake pans. Press firmly and evenly into the pans using the bottom of a glass or clean hands. Bake for 10-12 minutes or until edges are just golden. Remove from oven to cool before adding the cake batter.
Make the cake layers:
- In a large mixing bowl, whisk together the sugar, oil, sour cream, and buttermilk until smooth. Add the egg and vanilla and whisk until fully incorporated.
- In a separate bowl, whisk the sifted flour, sifted cocoa powder, baking soda, baking powder, and salt until evenly combined. Gradually mix the dry ingredients into the wet and whisk about 2 minutes, occasionally scraping down the sides of the bowl, until thoroughly combined without lumps.
- In a microwave-safe measuring cup, microwave 1/2 cup water until boiling, then stir in the espresso to dissolve.
- While constantly stirring the batter, gradually mix in the hot coffee. Mix until smooth and even in consistency (making sure to scrape the sides and bottom).
- Divide batter into cake pans over the pre-baked crusts. Bake for about 20 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
- Remove the cakes from the oven and allow them to cool in the pan for 30 minutes. Then, remove the cakes from the pans and finish cooling on a wire rack to room temperature. Wrap the cakes in plastic wrap and chill in the fridge for at least a few hours before assembly.
Make the toffee sauce:
- Melt the butter in a medium saucepan over medium heat. Add the brown sugar, heavy cream, and salt. Stir the mixture with a rubber spatula until fully blended. Bring the mixture to a boil and boil for 5-6 minutes, occasionally scraping down the sides of the pan.
- Remove the sauce from the heat, then stir in the vanilla. Transfer to a heat-proof container to cool to room temperature. (It will thicken as it cools.)
- If not using immediately, store covered in the refrigerator. Bring to room temperature and stir when ready to use. The consistency should be thick but just pourable.
Make the ganache:
- Microwave cream in a microwave-safe measuring cup or bowl until nearly boiling (about 30 seconds, then in 10-second increments if needed). Pour the hot cream over the chocolate chips and cover with foil. Cover with foil and let it sit about 4 minutes, then stir until smooth and no lumps of chocolate remain. Set aside to cool to room temperature.
Make the buttercream:
- In a heatproof mixing bowl or bowl of a stand mixer, whisk together sugar and egg whites. Place the bowl over a saucepan of simmering water (about 1 inch of water, not touching the mixing bowl). Cook, whisking continuously, until the egg whites are heated through and the sugar is fully dissolved (no longer grainy to the touch), about 3-4 minutes. (It’s important that there is no fat in the meringue mixture, or it will never reach stiff peaks. Make sure the eggs are cleanly separated and there is no grease on your mixing bowl or utensils before starting.)
- Transfer the bowl to the stand mixer and fit with the whisk attachment (or fit an electric mixer with the whisk attachment). Beat at medium-high speed until stiff, glossy peaks form and the bowl and meringue are cool to the touch, 7 to 8 minutes.
- Add butter, 1-2 tablespoons at a time, beating until combined after each addition. (The butter should be soft enough to indent with your fingertip, but not greasy or melty.) Once all the butter is added, scrape down the sides of the bowl and beat on medium-high until light and fluffy, about 1 minute. (Expect the buttercream to break into curdles before coming together; just keep beating until smooth!)
- Add vanilla and salt, and beat at medium speed until combined. Gradually mix in melted chocolate, and beat just until combined.
Assemble:
- Use a large serrated knife to even the tops of the cakes.
- Smear some buttercream in the center of a cake board, and place the first cake layer on it crust side down. Pipe a rim of buttercream around the perimeter of the cake to create a wall for the fillings.
- Spread on a layer of ganache, then a thick coating of toffee sauce (both at room temperature). Place the cake in the fridge for several minutes to set before stacking any further.
- Add a generous handful of chopped Heath bar over the toffee layer. Place the second cake layer on top, and repeat the buttercream border and fillings if making 3 layers.
- After adding the final cake layer, place the cake back in the fridge for a few more minutes to set before frosting, if needed.
- Start with a "crumb coat” of buttercream on the top and sides of the cake, then chill again and add your final coat of frosting. If desired, use extra ganache for piping or decorating.
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