Assemble all your ingredients, got everything? Good.
Before starting, set out the butter, sour cream, and eggs so they reach room temperature.
Preheat the oven to 350F. Use butter or cooking spray to grease three round 8-inch cake pans then flour the surface area of the pans.
In a large bowl, combine the flour, baking soda, baking powder, and ¼ tsp salt. Whisk together.
Boil 2 cups of water, then add 1 ¼ cups to a second bowl. Chop the chocolate then add it with the cocoa and instant coffee. Whisk until smooth.
In a new bowl, add 10 tbsp of the softened butter and the sugar. Beat with a mixer or using a spatula until light and fluffy (this will take about 3 minutes with an electric mixer).
Once light and fluffy, add the eggs one at a time, beating after each one until mixed. Add the sour cream and 1 tsp vanilla.
Slowly add the black food dye and mix after each addition until you achieve the desired color. Depending on what type of dye you use, you will require different amounts.
Alternate adding the flour mix and chocolate mix until it’s all incorporated. Make sure to scrape down the sides so everything gets mixed in!
Divide the batter between the three pans and smooth the surface. Put in the oven and bake for 20 minutes or until you can insert a fork in the middle and it comes out clean.
Let the cakes cool while still in the pans for 15 minutes before transferring to a wire rack to cool completely.
While you wait for the cake to finish cooling, you can make the frosting. It is best if you use a stand mixer or electric hand mixer for this. Add the rest of the softened butter to a bowl along with ½ tsp salt and whip until soft and smooth.
Slowly add the sugar and ½ tsp vanilla then whip again until smooth, or for 2-5 minutes. Make sure to scrap down the sides of the bowl so everything gets mixed.
Add the marshmallow fluff and continue whipping for 5 minutes or very light and fluffy.
Separate 1 ¼ cups of frosting and set aside. Divide the remaining frosting evenly between three bowls. In one bowl, add orange food coloring bit by bit and mix. Continue adding food coloring until you reach the desired shade. In the second bowl, do the same with the yellow dye. Leave one bowl white.
Frost the top of one of the cakes with the yellow frosting, reserving enough to put on the sides later. Place the second cake on top of the yellow-frosted one and repeat with the orange frosting.
Place the third cake on top and spread with the white frosting. This time, spread the white frosting down the sides of the cake, focusing on the top third if you are running out of frosting. Put the cake in the fridge for at least half an hour to allow the frosting to set.
After half an hour, spread the rest of the yellow frosting along the bottom third of the cake, the rest of the orange frosting along the middle third of the cake, and the rest of the white frosting along the top third of the cake.
Run your offset spatula around the sides of the cake to smooth the frosting and lightly blend the edges together without smudging.
To decorate, place the candy corn along the rim of the cake, alternating pointy side and base side. Use the remaining white frosting to put little dots inside the candy corn ring. This can be achieved using a piping bag and tip or putting the frosting into a Ziploc bag and cutting a small corner off the top.
Before serving, refrigerate 30 minutes to set the frosting again. Enjoy!