Raspberry Chocolate Cake

First, make the raspberry filling. In a saucepan over medium heat, combine the raspberries, 2 tablespoons of the sugar, cornstarch and lemon juice. Cook the mixture over medium-low heat, stirring constantly with a silicone spatula, until the raspberries have broken down completely and filling is a thick consistency, about 8 minutes. Taste the filling a you make it and add more sugar if it tastes too tart. Remove the pan from the heat, stir in the vanilla extract and set aside to cool, about 30 minutes
Next, make the cakes. Preheat the oven to 350°F. Grease and line two 8-inch cake pans with parchment paper. Set aside.
In a large bowl, whisk together the sugar, cocoa powder, flour, baking powder, baking soda, and salt.
Make a well in the center of the dry ingredients and add the oil, vanilla, eggs, and buttermilk. Starting from the center of the bowl whisk, pulling all the dry ingredients into the wet. Whisk just until no streaks of flour remain. Pour in the brewed coffee, mixing until just combined.
Divide the batter evenly among the prepared pans and bake for roughly 30 minutes, or until a knife inserted in the center of the cake comes out clean. Cool completely on a wire rack before frosting.
Once the cakes have cooled, make the frosting. In a stand mixer fitted with a paddle attachment, cream the butter and cocoa powder on low speed for 30 seconds. Add in the confectioners’ sugar, warmed milk, corn syrup, vanilla, and salt. Beat on medium speed, scraping down the sides and bottom of the bowl as needed, until the frosting is fluffy and has lightened in color slightly, about 30 seconds.
Place the first cake layer right side up onto a cake stand or plate. Spread a large dollop of frosting on top, using an offset spatula to spread it out so it is higher on the edges than the middle, creating a wall to hold the raspberry filling in. Top with the cooled raspberry filling, spreading it into an even layer, Use the the remaining frosting to frost the sides of the cake. Use the back of a large spoon to create swirls around the top and sides of the cake. If using, top the top of the cake with raspberries all over. Slice and serve!