Grease and flour three 9-inch cake pans. Preheat the oven to 350 degrees F.
Mix together the flour, baking powder, baking soda, salt, and spices together. Set aside.
Beat the butter, oil, and both sugars together until light and creamy. Add in the eggs, one at a time and beat very well between each egg. Add in the vanilla, and then the pumpkin puree. Alternate between adding the flour and the milk to the batter, beginning and ending with the flour. Do not overmix.
Evenly divide the batter between the three cake pans. Bake for about 25 – 30 minutes, or until a toothpick inserted in the middle comes out clean. Remove from the oven and allow to cool in the pans for about an hour before removing and allowing to cool completely on wire racks.
For the Ginger Chocolate Frosting
Beat the butter until smooth and creamy. Add the melted chocolate and stir until combined. Add in the remaining ingredients and mix until well combined. Tip: mix the frosting on the lowest speed with the paddle attachment to ensure any air bubbles in the frosting are beaten out.
For the Meringue
Whisk together the egg whites, sugar, and salt just until mixed together. Place over double boiler and whisk constantly until the sugar is dissolved. Return to a stand mixer, or beat with a hand mixer until stiff, glossy peaks form and the bowl is cool to the touch. Beat in the vanilla and cinnamon
Assembly
Level the cake as necessary and cut off the edges around the cake if desired. (I find this is all easier to do after leaving the cakes in the freezer for a few hours). Take half the ginger chocolate and place on one cake. Top with another cake and the remaining ginger chocolate frosting. Top this with the last cake. Spread the meringue around the sides and top of the layered cake. The cake looks best when you make swooping swirls all around. Use a kitchen torch to toast the meringue. Make sure you really toast any bumps and curls in the meringue to make them really pop
Notes
Store in an airtight container for up to five days