Preheat the oven to 350°F. Spray six 8-inch round cake pans with nonstick cooking spray and line the bottom of each pan with a circle of parchment paper. (If you have fewer pans, see the note about baking in batches.)

In a large bowl, whisk together the flour, cocoa powder, baking powder, and baking soda.

In a separate large bowl or the bowl of a stand mixer, beat the granulated sugar, vegetable oil, eggs, and vanilla extract on medium speed until smooth and well combined, about 2 minutes.

Add the dry ingredients to the wet ingredients and mix on low speed just until combined. With the mixer on low, slowly pour in the hot water and mix until the batter is smooth. The batter will be thin. Do not overmix.

Divide the batter evenly between the six prepared pans (a kitchen scale helps). Bake for 25 to 30 minutes, or until a toothpick inserted into the center of each cake comes out clean.

Let the cakes cool in the pans for 30 minutes. Run a knife around the edge of each pan to loosen the cake, turn the layers out onto a wire rack, peel off the parchment, and let them cool completely, about 1 hour.

Level each cooled cake with a cake leveler or long serrated knife to remove the domed top. Discard the tops or save them for cake pops or cake truffles.

For the filling, beat the softened cream cheese with a hand mixer or stand mixer on medium speed until smooth, about 2 minutes. Gradually add the powdered sugar on low speed, beating until all of the sugar is incorporated.

Add the pumpkin puree, heavy whipping cream, vanilla extract, cinnamon, nutmeg, and cloves. Beat on medium-high speed until smooth and fluffy, 1 to 2 minutes. If you want to pipe decorations on top of the cake, set aside a small amount of filling in a piping bag.

To assemble, place one cake layer cut side down on a cake plate. Spread about ⅙ of the filling evenly over the top. Repeat with the remaining cake layers and filling, finishing with a layer of filling on top. Scrape any filling that squeezes out along the sides of the cake to lightly frost it.

Sprinkle the chopped pecans over the top of the cake and pipe any reserved filling, if using. Refrigerate for at least 1 hour so the filling sets before slicing.