• Adjust the oven racks, place the rack in the middle of the oven and preheat the oven to 350 F or 180 C. Prepare two 8 inches cake pan or three 6-inch cake pan with nonstick cooking spray or use my homemade magic pan release spread. Set aside.
• In a medium bowl, combine the flour, baking powder, salt, and nutmeg together and whisk well to combined and set aside.
• In a separate bowl or in a bowl of a stand mixer, cream the butter and sugar until very light and fluffy and has changed color from cream to white, about 5 minutes. Add the egg white and whole eggs one at a time and mix well after each addition until all is added. Scrape down and add the vanilla extract and mix again to combined.
• While the mixer is running low, add a third of the flour mixture to the batter and mix. Next add half of the buttermilk to batter and mix to combine. Continue alternating adding flour and buttermilk until finished. Scrape down with a rubber spatula and stir the mixture twice to make sure everything is well incorporated.
• Pour the cake batter into the prepared cake pans and smooth the top with an offset spatula. Bake the cakes in the preheated oven for 30 – 35 minutes or until they are risen and firm or when toothpick inserted into the center and comes out clean and dry. Cool the cakes in the pans for about 10 minutes before moving onto wire rack to cool completely.

Assembly the cakes

• After the cakes have cooled completely, then tort and level the cakes for a flat top for easy decoration. Check this post on how to tort and level cakes easily. I used this buttercream recipe for icing the cake.

  To assemble the cake, place a nonslip mat on a turntable and then tape a 6 inches cake cardboard circle to an 8 inches cardboard circle (the8 inches cardboard helps to transport the cake to the fridge and back easily)and place the cake board on the turntable.

  Apply a small amount of buttercream to the center of the 6inches cake board. Place the first cake layer on the board and add enough buttercream onto the cake and smooth the buttercream as level as you can get(check the visual guideline above).

  Place another cake layer on top of the frosting and repeat the process until all the cakes are stacked. The last cake layer should be placed flat side up that is the bottom should face up. Press down on the stacked cakes lightly to help the cakes stick to the icing.

Decorating the cake

• Tint the remaining buttercream green, then crumb coat the cake with a thin layer of buttercream and smooth it with a cake scraper. Refrigerate the cake for about 30 minutes or 10 minutes in the freezer. Bring the cake out and add enough buttercream to the sides and top. Smooth with icing scraper. Roll out dark brown and light brown fondant. Cut out 1-inch squares to decorate the bottom of the cake.

  Roll out green fondant and cut 1 x ½ inch stripes to go on top of the brown fondant pattern (check the cake for a visual clue).

  Decorate with a sonic cake topper, serve, and enjoy.