Preparing the Cake Batter

Before you get started, make sure to preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan to ensure that the cake comes out easily once it’s baked. Begin by preparing the cake batter. In a large bowl, sift together the dry ingredients from the cake mix—flour, sugar, cocoa powder, baking powder, baking soda, and salt. Sifting ensures that the dry ingredients are well-combined and helps prevent any lumps in the batter.

In a separate bowl, beat together the wet ingredients—eggs, milk, oil, and vanilla extract—until smooth and combined. Once the wet ingredients are well incorporated, gradually add them to the dry ingredients, mixing until the batter is smooth. The key is to blend everything together well so the cake has a uniform texture. Once you’ve mixed the wet and dry ingredients, you’ll need to stir in the boiling water. This step might seem unusual, but adding hot water to the batter helps to create a thinner consistency, which results in a moist, tender cake. Don’t worry if the batter looks thin—it’s the consistency you want for this recipe.

Baking the Cake

Once the batter is ready, divide it evenly between the two prepared cake pans. The pans should be greased and floured to prevent sticking, and it’s important to distribute the batter evenly to ensure the cakes bake uniformly. Place the pans in the preheated oven and bake for 30 to 35 minutes, or until a toothpick inserted into the center of the cakes comes out clean. If you want to make sure the cake is perfectly baked, try checking a few minutes before the recommended time—oven temperatures can vary.

Once the cakes are done baking, remove them from the oven and let them cool in the pans for about 10 minutes. Afterward, carefully remove the cakes from the pans and place them on a wire rack to cool completely. This is a crucial step, as the cake needs to be completely cool before adding the caramel layer and whipped topping.

Adding the Caramel Layer

Once the cakes are cool, it’s time to add the caramel layer. Using a fork, poke several holes in the top of each cake. The purpose of this is to allow the caramel and sweetened condensed milk mixture to seep into the cake, infusing it with rich, gooey caramel goodness. In a bowl, combine the sweetened condensed milk with the caramel topping until smooth. Once combined, evenly pour this mixture over the top of each cake, making sure that it seeps into the holes you’ve poked. The caramel should cover the surface of the cakes and fill the holes, ensuring that every bite of the cake will have a delicious caramel flavor.

Layering the Whipped Topping and Heath Bars

Next, it’s time to add the whipped topping. Spread a layer of the thawed whipped topping over the caramel-soaked cake, smoothing it out to cover the surface evenly. The whipped topping adds a light, creamy texture that contrasts beautifully with the rich caramel and the dense cake below. It’s the perfect way to balance out the cake’s sweetness while adding an airy element to the dessert.

Once the whipped topping is evenly spread, sprinkle the crushed Heath bars (or Heath bits) generously over the surface. This is the final touch that gives the cake its signature toffee crunch. The toffee bits provide a delightful contrast to the softness of the cake and the creaminess of the topping. They also add a satisfying crunch that enhances the overall texture of the cake, making each bite an exciting mix of soft, crunchy, and creamy elements.

Chilling the Cake

The final step before serving is to let the cake chill in the refrigerator for at least an hour. This allows the layers to set properly and makes the cake easier to cut into neat slices. Chilling also helps the flavors to meld together, making the cake even more delicious after it has had time to rest. While it’s tempting to dig in right away, patience here pays off—it’s worth the wait!