Preheat oven to 350 degrees F. Line 3 6-inch cake pans with a round of parchment, then spray with non-stick spray.
Prepare cake according to box instructions. Divide batter evenly into prepared pans, then bake 22-25 minutes.
Cool in pans 10 minutes, then transfer to cooling rack to cool completely.
Wrap cooled cakes in plastic wrap and refrigerate or freeze.
For the buttercream:
Whip butter until creamy.
Reduce speed to low and add powdered sugar 1 cup at a time until well blended.
Increase speed to medium and beat for 3 minutes until fluffy.
Add vanilla and cream and continue to whip on medium for 1 minute.
Add more cream as needed until desired consistency is reached. Whip until the frosting is smooth and silky.
For the ganache:
Prepare the ganache so it can cool while you are putting the cake together.
Bring heavy whipping cream just to a simmer then pour over chocolate chips, making sure the chocolate is fully covered.
Let set for 5 minutes.
Whisk gently to combine cream, chocolate, and food coloring. Set aside to cool.
To assemble the cake:
When ready to assemble, trim the dome off of all cake and reserve for another use (or eat it!)
Place one layer of cake on a cake stand or serving plate. Pipe a ring of buttercream around the edge, then spoon in jam filling.
Repeat with remaining layers.
Apply a thin coat of frosting all over the cake. Chill for 20 mins. Use the remaining frosting to coat the cake.
Use freshly made ganache for drips (make sure your cake is very cold so ganache sets quickly).
Using a spoon, spoon the ganache around the top edge of cake allowing it to drip down the sides.
Serve with a meat cleaver if you'd like!
The calories shown are based on the cake being cut into 12 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**