Put the rack in the middle of the oven and preheat to 350° F/175° C.
In one medium bowl, whisk together the unbleached all-purpose flour, white whole wheat flour, baking powder, baking soda, cinnamon, ginger, allspice, cloves, and salt. In the other medium bowl, whisk together the pumpkin puree, buttermilk, molasses, and vanilla.
In the bowl of the stand mixer, beat together the softened butter and brown sugar and the mixture is creamed. Add the eggs one at a time and beat until the eggs and fully mixed in.
Add one third of the flour mixture and mix in on low, then add half the pumpkin mixture again mixing on low. Repeat with one third of the flour mixture, then the remaining pumpkin mixture, and then the remaining flour mixture just until the flour is mixed in. Don’t over mix. Divide the batter evenly between the three prepared cake pans. Tap the cake pans lightly on the counter to remove any bubbles.
Bake in the preheated oven until a toothpick comes out clean, about 25 to 28 minutes. Cool in the pans on wire racks for 10 minutes, then run a plastic knife around the insides of the pans to release the cakes and turn them out onto the racks to cool completely before frosting.
In the bowl of the stand mixer, beat the cream cheese and butter together until creamy. Add the sifted confectioners sugar and mix until it has no lumps. Add the dulce de leche and mix until it is thoroughly combined.
Assemble and Bake
Place one cake layer on the cake stand and spread one-third of the frosting on it, then sprinkle one-third of the toasted coconut on it. Repeat with the second layer, and repeat with the top layer.
If you don’t have buttermilk, you can make it by pouring 2 teaspoons of lemon juice into the measuring cup then adding some low-fat milk until you have the required amount. Then let it rest on the counter about 10 minutes until it sours. The cake is very moist and will keep for a couple days.