Preheat the oven to 350 degrees Fahrenheit. Grease and line two 8 or 9 inch round cake pans with parchment paper. I like these parchment rounds. In a large mixing bowl or bowl of a stand mixer, add the melted butter, oil and sugar. Beat to combine for about 20 seconds.
Add in the eggs, milk, vinegar and vanilla. Beat to combine.
Add in the flour, cocoa powder, baking powder, baking soda and salt. Beat to combine, then with the mixer running on low, slowly pour in the hot coffee or boiling water until you get a smooth consistency. Careful not to over mix.
Divide the batter among your two pans. Add to the center rack in the oven and bake for 35-45 minutes (will depend on if you used 8 or 9 inch pans) or until a toothpick comes out clean.
Let cool in the pan for about 15 minutes, then flip onto a wire rack to finish cooling. If the tops have domed at all, flip back so the domed side is facing up, this will prevent cracking. Once the cake has cooled, you can use a cake leveler or a sharp knife to level off the top. Meanwhile, combine the ingredients for the raspberry filling in a small pot on the stove. Let simmer over medium heat, using the back of a fork to smash the raspberries. Once the mixture starts to bubble a bit, mix well then remove from the heat to let thicken.
To make the frosting, add the softened butter to a large bowl or bowl of as stand mixer. Beat for about 2 minutes until fluffy. Beat in the cocoa powder until well combined, then add in the powdered sugar and beat for about 1 minute. mix in the heavy cream or milk plus the salt and vanilla. Mix for 1 more minute. If it is too thick, you can add in a bit more milk. If you want it thicker, add in more cocoa or powdered sugar.
Once the cakes have fully cooled, assemble by adding about 1 1/2 cups of frosting to one layer (I like to makea bit of a well in the center with the frosting higher on the sides to contain the jam) then top with 1 cup of the raspberry filling. Add the second cake layer and frost the top and sides with the remaining frosting.
Top with any remaining raspberry jam plus fresh raspberries and a dusting of powdered sugar if desired. Enjoy!