First prepare the pumpkin cake recipe DOUBLED as per the instructions on that blog post & divide the batter between 3- 9" (or 8") square pans that have been greased and parchment lined.
If you do not have 3- pans it is OK to let the batter sit on the counter while the others bake.
While the cake is cooling, prepare the buttercream as per the instructions on that blog post and add the last stage of mixing add all the spices.
Prepare the ganache recipe DOUBLE recipe and let cool at room temperature to a pour able consistency while you assemble the cake
Assemble the cake as shown in the video tutorial
Notes
Cake is best served at room temperature and can be stored at room temperature for up to 4 days.
For longer storage keep in the refrigerator for up to 9 days
Recipe by Gretchen's Vegan Bakery at https://www.gretchensveganbakery.com/halloween-graveyard-cake/