Pre heat oven to 350°. Prepare 3, 8'' cake pans by spraying the bottom and sides with cooking spray, lining the bottom with a parchment paper round, then spray again. Set aside.
In a Large bowl, or the bowl of a stand mixer, combine the flour, sugars, baking powder, salt, cinnamon, and nutmeg. Stir with a whisk to sift together.
Cut butter into dry mixture until small crumbles remain. No large chunks of butter should be there.
In a separate bowl, combine buttermilk, eggs, pumpkin, and vanilla and whisk together.
Pour half of wet mixture to the dry, stir to combine. Add the rest of the wet ingredients and mix until smooth and fluffy. Add in the chcocolate chips and fold in.
Pour batter into pans and smooth out the top. Bake in oven for 20 minutes or until a toothpick comes out clean. Let cool in the pan for 15 minutes, then turn onto a wire wrack to cool completely. Layers can be wrapped in cling wrap and frozen until ready to assemble.