For the Cake

1. Preheat the oven to 350°F. Prepare three 6-inch round baking pans, line the bottom with parchment paper, and grease the sides.
2. In a large mixing bowl, combine the sugar, vegetable oil, eggs, and vanilla extract. Beat on medium speed until well incorporated. Next, mix in the sour cream and beat until well combined.
3. In a separate bowl, sift together the dry ingredients. To the batter, alternate adding half the dry ingredients followed by half of the coffee, and mix just until the flour starts to incorporate. Repeat with remaining ingredients. Use a spatula to scrape down the sides of the bowl and stir the batter from the bottom to the top to ensure it’s well mixed.
4. Divide the batter evenly between the three pans, it’s around 2 cups per layer. Bake at 350°F for 28-35 minutes. Test the cake for doneness by inserting a toothpick into the center of the cake. If the toothpick comes out clean, the cake is done. Remove from the oven and allow to cool completely.

For the Buttercream

1. Cut butter into pieces. Using the paddle attachment, whip the butter for 5-7 minutes, scraping down the bowl occasionally. Beat until the butter looks light in color.
2. Alternate adding 2 cups of powdered sugar at a time with the liquid ingredients: vanilla extract & heavy cream. Add the salt. Ensure the powdered sugar is well combined, then whip for 1-2 minutes before adding the next cups of powdered sugar.
3. Once all the powdered sugar has been added, increase speed to medium-high and beat for another 3 minutes or so until it’s light and fluffy. Then turn down the mixing speed. Add a few large drops of electric blue along with one drop of royal blue and mix at a low speed, scraping down the bowl as needed. Add additional color until you reach the desired effect.
4. Fondant: Prepare the black and white fondant squares by rolling out each color to a thin but even thickness, but not less than 1/8” thick. Use a square cookie cutter (mine was 5/8” wide) and cut the squares out (estimate about 30 squares of each color). Set aside, or place in a single layer in a flat, airtight container to be used later. These are best placed on the cake while the buttercream is fresh (and best if you’re not refrigerating the cake), otherwise you can attach them but taking a toothpick to gently scratch the buttercream before applying.

To Assemble

1. Use a cake leveler to cut the domes off the top of the cake so all 3 layers are even and flat.
   If you want to dowel the cake, stack them on top of one another and cut the dowel about 1/8 of an inch above the top layer of cake. Also, place 2 dowel holes in a 6-inch cake board, one on each side. Set the dowel side.
2. Assemble the top 2 layers first. Using 1 cup of frosting between the layers, spread it evenly with an offset spatula, and then add a light crumb coat around the outside. Fill a large piping bag, cut off about 1 inch up from the bottom. Pipe a thin layer of frosting along the outside edge of the cake, filling in any additional gaps between the layers, and a thin layer of buttercream on top of the cake. Then, use an offset spatula or icing scraper to wipe away the excess frosting, leaving just enough to coat the outside of the cake. Do not mix the crumb-coating frosting back into the bowl if it has cake debris in it. Refrigerate the cake for 15-30 minutes until the outside layer is chilled.
3. For the bottom layer, lay a piece of track between the two, cutting out the middle of the cake. Leave yourself a little extra space on each side. Crumb coat each half, all the way around the cake, including the inside edge. Place a thin strip of parchment paper along the inside edge of the cake. Then, using about ½- ¾ cup of buttercream, frost the top of each layer, place a cake board on top, and place the dowels through the cake board and bottom layer of the cake.
4. Next, place the top 2 layers (assembled and chilled) over the dowels. Once the cake is stacked, apply another liberal crumb coat to the entire cake, making the sides as even and flat as possible. Chill for 20-30 minutes until the buttercream is set.
5. Using the remaining buttercream, fill a couple of large piping bags, cut off about 1 inch up from the bottom. Pipe a layer of frosting along the outside edge of the cake, working your way from top to bottom. Add a thin layer of buttercream on top of the cake.
6. Next, use an icing scraper to smooth out the frosting. First, run it under very hot water and dry thoroughly. Lightly press the scraper up against the side of the cake at a 90-degree angle, rotate the cake in a circle, applying even pressure on the scraper. Stop halfway through and clean off the scraper, run under hot water, and dry before starting again. Repeat these steps until the buttercream is smooth. Any gaps can be filled in with the additional frosting and rescraping. It may take several rounds of scraping. Finally, add a thin layer of buttercream on top of the cake and spread evenly. If possible, I recommend placing the middle piece of track through the cake and just leaving it there until you’re ready to serve.