1 1/2cups(3 sticks) unsalted butter, room temperature
5cupspowdered sugar, sifted
For the cake
Preheat oven to 350F and butter 2 8-inch cake pans. I like to place a circle of parchment paper at the bottom of my cake pans as well to insure easy removal.
Whisk together the flour, baking powder, salt, cinnamon, and nutmeg and set aside.
In the bowl of a stand mixer with the paddle attachment, beat the butter and 2 sugars together about 5 minutes, until very light and fluffy. Add the eggs one at a time and beat well after each addition.
Add the apple butter and the milk, and mix briefly to combine.
Add the flour mixture, about 1/3 at a time, and mix briefly to combine but don't over mix.
Give the batter a final stir by hand to make sure there aren't any pockets of unmixed ingredients, and then divide the batter into the two prepared baking pans.
Bake for about 25-35 minutes until risen and a toothpick inserted into the center of the cake comes out clean.
Remove from the oven and allow to cool for a few minutes in the pan before turning out on to a baking rack to continue cooling. Allow the cake layers to cool completely before frosting.
For the buttercream
In a stand mixer with the paddle attachment, add the butter and salt and beat for a minute or so until very smooth. Add the powdered sugar, about a cup at a time, beating between each addition. Scrape down the sides of the bowl as needed to get everything fully incorporated. Add the molasses and cream and continue to beat until everything is smooth and well mixed. Note: if your frosting seems a little too thick, add a touch more cream or molasses, but go slowly. If your frosting is a little loose, blend in a little more sifted confectioner's sugar.
Frost the top of one layer with a generous amount of frosting.
Stack the second layer on top, and frost the sides, and finally the top.
For the frosting, use regular molasses, not 'blackstrap', which is bitter.
This cake has a moist dense texture, and can easily be sliced into very thin pieces, making it ideal for serving a crowd (or midnight snacking.)