This decadent Chocolate Raspberry Cake Recipe has a homemade chocolate cake, tangy raspberry filling made from fresh raspberries, and frosted with a rich chocolate buttercream frosting.
In a medium saucepan, add in the sugar and cornstarch. Stir until combined.
Add in the raspberries, lemon juice, and water. Stir until the raspberries are coated with the sugar and cornstarch mixture.
Place over medium heat and let come up to a boil while occasionally stirring.
Once the mixture comes up to a boil, allow to boil for 3 minutes while stirring constantly.
Remove from the heat and place in a heat-proof bowl. Place a piece of plastic wrap on top, gently pressing it down until it touches the sauce, and place in the fridge to chill and set up for about 4 hours.
If you would like the sauce to be seedless, once you remove it from the heat, pour half of the sauce into a fine-mesh strainer that's sitting on a mixing bowl. Use a spatula to work the sauce through the sieve. Discard the seeds. Repeat with the remaining half of the sauce. Then place the plastic wrap on the bowl, gently pressing it so it touches the top of the sauce, and place it in the fridge.
Chocolate Cake
Preheat oven to 350 degrees F and spray two 8 inch cake pans with nonstick baking spray. Place a parchment circle in the bottom of each pan and add about 1 tablespoon of flour or cocoa powder to dust the sides of the pan. Gently tap the pan and turning it while it's on its side to coat the sides of the pan. Tap out any excess flour.
In a medium bowl, add in the melted butter, vegetable oil, and cocoa powder. Whisk until smooth.
Add in the buttermilk, sour cream, and vanilla. Whisk until incorporated.
Whisk in both of the eggs until combined.
In a large mixing bowl, add in cake flour, sugar, baking soda, baking powder, and salt. Whisk until blended.
Pour the wet ingredients into the bowl with the dry ingredients. Whisk until everything is combined and most of the lumps have disappeared.
Divide the batter evenly into the two prepared cake pans.
Place into the preheated oven and bake for 28 to 33 minutes or until a toothpick inserted into the center of the cakes comes out clean or with moist crumbs.
Remove from the oven and allow to cool about 15 minutes in the pan before turning out onto a wired rack to cool completely.
Chocolate Frosting
Add the butter, 4 cups powdered sugar, cocoa powder, vanilla extract, and ¼ cup of heavy cream in a large mixing bowl. Beat until creamy and smooth.
Add in the remaining 4 cups of powdered sugar and the remaining ¼ cup of heavy cream to the bowl. Beat until the frosting is light and fluffy.
Cover with plastic wrap until ready to use.
Assemble the Cake
Using a cake leveler or cake knife, cut the cooled chocolate cakes in half.
Add about ⅓ of the frosting to a piping bag fitted with a Wilton 1M piping tip.
Swipe a small amount of frosting to the center of the cake plate.
Place one layer of the cake on a cake plate, cut side down. Gently press down.
Pipe a ring of frosting around the inside edge of the cake.
Add ½ cup (a little less if you're using seedless sauce) of raspberry sauce to the center of the cake layer. Spread evenly out with an angled spatula.
Add the next layer of chocolate cake cut side down and gently press it down until the frosting squishing and the cake layer is even.
Repeat with adding the frosting, raspberry sauce, and layers of cake until you get to the last layer of chocolate cake.
Add a big dollop of chocolate frosting on top of the cake. Make sure it's more than you think is needed to frosting the top so it gets pushed over the edges of the cake.
Using a large angled spatula, begin spreading the frosting out. If you're finding the cake is moving a lot, I use my thumb and index to hold the layer on the opposite side of where my angled spatula is and move the spatula towards my thumb and index finger.
Once the frosting is smoothed out, add frosting to the sides of the cake and begin smoothing it out evenly.
For a smoother finish, dip the angled spatula in hot water. Wipe off the water and slowly move it straight up and down along the frosting. Repeat every time you pull the spatula area from the frosting.
Pipe swirls of frosting on top of the cake with the remaining frosting in the piping bag. You can add more frosting if needed.