Preheat the oven to 350F/177C. Line three, 8-inch (20-cm) round cake pans with parchment paper and spray the sides with a baking spray.
In a large mixing bowl, combine the buttermilk, oil, eggs, vanilla and sugar. Mix on medium speed for about 3 minutes, until the eggs are well beaten. Melt the chocolate chips in the microwave or in a double boiler. Mix the melted chocolate into the batter for about 1 minute, until well combined.
In a separate bowl, combine the dry ingredients: flour, baking soda, baking powder, salt and cocoa powder. Sift the dry ingredients into the wet ingredients and mix on medium speed for about 1 minute, just until the ingredients are incorporated. Do not overmix!
Divide the cake batter evenly between the three pans and press 1 ½ cups of fresh or previously frozen berries into the batter, spacing the berries evenly. If using frozen berries, make sure to thaw them first!
Bake the cake layers in the preheated oven for 24 to 26 minutes, or until a toothpick inserted into the center comes out clean. Once the layers are baked, remove them from the pans onto a wire rack to cool completely.
Meanwhile, prepare the Raspberry Buttercream. I have a separate video recipe for this frosting, linked in the post above and instructions below: https://tatyanaseverydayfood.com/raspberry-buttercream/
For the filling, place 1 ½ cups raspberries into a bowl and use a large fork to crush the berries.
Assembling the Cake:
Once the cake layers have cooled completely, use a sharp serrated knife to level off the top of each layer, if needed. Next, use a pastry brush to lightly soak each cake layer with the raspberry liqueur.
To assemble the cake, first spread a thin layer of frosting onto the first cake layer. Transfer some of the buttercream into a pastry bag tipped with a simple round tip or a star tip; I used Ateco tip #847. Pipe a barrier ring around the edge of the cake, then fill the center with half of the crushed raspberries. Watch my video recipe to see how it’s done.
Add the next cake layer and repeat the same process. After adding the last cake layer on top, frost the top and sides of the cake with a light crumb coat of frosting. Refrigerate the cake for 15 to 20 minutes, then add the final coat of buttercream. Garnish the top of the cake with dollops of buttercream and fresh berries.
The cake can be enjoyed immediately or stored for the next day in the refrigerator. When ready to enjoy the cake, remove it from the refrigerator an hour or 2 prior to allow the cake layers to soften.
For Raspberry Buttercream:
Prepare the raspberry sauce first. Place the raspberries and granulated sugar into a small saucepan and bring the berries to a simmer over medium heat. Simmer for 4 to 5 minutes, until the berries start to fall apart and form a jam. Pour the jam into a fine mesh strainer arranged over a mixing bowl. Use the back of a spoon or a spatula to press the sauce through the strainer, leaving the seeds behind. Discard the seeds and place the sauce into the refrigerator to chill.
Next, prepare the buttercream. The butter needs to be just slightly softened, not melted. If the butter is too soft, return it to the refrigerate to chill. Place the softened butter into a mixer bowl and whisk on high speed for 7 to 10 minutes, until the butter is fluffy, creamy, and pale white in color. Make sure to scrap down the sides of the mixing bowl often to ensure all the butter is well-mixed.
Add the confectioner’s sugar next and start mixing on low speed first until the sugar is incorporated. Once all the lose sugar is incorporated, turn the mixer to high speed and whisk for 3 to 4 minutes, until the buttercream is light and fluffy. Scrap down the sides of the mixing bowl periodically to make sure everything is well mixed.
If desired, add a few drops of red food coloring at this time. For a sourer buttercream, add the citric acid. For even more raspberry flavor, add raspberry extract. Add the chilled raspberry sauce last! Add the sauce and mix for about 15 to 20 seconds, 30 seconds maximum, with the mixer. Do not overmix or this will cause the buttercream to separate! Finish mixing in the sauce by hand using a spatula and use.