This wonderfully moist and generously spiced six-layer cake is a showy spin on humble applesauce cake.
Allow butter and eggs to stand at room temperature for 30 minutes. Meanwhile, lightly grease bottoms of three 8x1-1/2-inch round baking pans. Line bottoms of pans with parchment paper. Grease and lightly flour bottoms and sides of pans; set aside. In a large bowl, combine flour, baking powder, baking soda, salt and ginger; set aside.
In a large mixing bowl, beat butter with an electric mixer on medium to high speed for 30 seconds. Gradually add sugar; beat until well combined. Add eggs, one at a time, beating well after each addition. Add molasses and vanilla; beat until well combined (mixture will appear curdled). Alternately add the flour mixture and buttermilk to butter mixture, beating on low speed after each addition just until combined. Pour 1 cup plus 2 tablespoons of the batter into each prepared pan. Refrigerate the remaining batter.
Bake in a 375° oven about 15 minutes or until a wooden toothpick inserted near center comes out clean. Cool for 10 minutes in pans on wire racks. Remove from pans and completely cool on wire racks. Wash pans; line bottoms with waxed paper, grease and lightly flour. Repeat with the remaining batter.
In a medium bowl, combine applesauce, apple butter, and if you like, apple pie spice. To assemble, select the cake layer that's most attractive; set aside for the top layer. Place one of the remaining cake layers on a serving plate; top with about 3/4 cup of the applesauce mixture, spreading to within 1/2 inch of the edge. Repeat with remaining cake layers and applesauce mixture. Place reserved cake layer on top. Chill, covered, in the refrigerator for at least 6 or up to 24 hours before serving to make slicing easier and to allow applesauce mixture to moisten the cake.
Let cake stand at room temperature for 1 hour before serving. Just before serving, spread about 1 cup whipped cream on top; sprinkle with nuts. If you like, pass additional whipped cream.
Sour Milk To make 1 cup sour milk, place 1 tablespoon lemon juice or vinegar in a glass measuring cup. Add enough milk to make 1 cup liquid; stir. Let the mixture stand for 5 minutes before using.