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Homemade Chocolate Cake

Portal Cake

This homemade chocolate cake is over the top chocolatey and decorated to look like the cake from Portal! It is a three layer dark chocolate cake frosted with the best milk chocolate frosting! It is rich, moist and one of the best chocolate cakes ever!
Course Dessert
Cuisine American
Prep Time 30 minutes
Cook Time 25 minutes
Decorating 20 minutes
Total Time 55 minutes
Servings 16 people
Calories 577kcal
Author Lisa


Best Chocolate Cake

  • 1 teaspoon instant espresso
  • cup boiling water
  • cup special dark cocoa powder*
  • 1 cup buttermilk
  • 2 teaspoon vanilla extract
  • 2 ⅔ cup cake flour
  • 1 ½ teaspoon baking soda
  • ½ teaspoon salt
  • 2 ½ cup sugar
  • 1 cup unsalted butter
  • 4 extra-large eggs
  • 2 extra-large yolk
  • ½ cup vegetable oil

Best Chocolate Frosting- make 2 batches of this!

  • ½ cup butter melted
  • ½ cup cocoa powder
  • 5 cups powdered sugar
  • ¾ cup heavy whipping cream
  • 1 teaspoon vanilla
  • pinch salt

Portal Decorations

  • ½ block of chocolate almond bark
  • whipped cream
  • 8 cherries
  • 1 white candle


To make the best chocolate cake:

  • Preheat oven to Preheat oven to 350°F. Butter three 9 inch round cake pans, bottoms and sides, then sprinkle the pans with flour, then cut out parchment in circles to fit the bottom of the cake pans and place those in the pan.
  • Boil water and add espresso to it, stirring until dissolved.
  • Whisk cocoa powder, then buttermilk and vanilla into water/espresso mixture.
  • Sift flour, baking soda and salt into a separate bowl.
  • Using a stand mixer, whisk sugar and butter until fluffy. About 10 minutes.
  • Add each egg and the yolk, one at a time, into the butter mixture, letting each one fully mix into the batter before adding the next. Add in oil and mix until fully combined. The beat mixture on medium high speed for a minute- the mixture will be light and fluffy.
  • Fold in ½ of the flour and then fold in ½ of the buttermilk mixture to the batter. Then fold in remaining flour and then remaining buttermilk mixture.
  • Bake for 20-25 minutes or until a toothpick inserted comes out clean. Try baking the cakes on the same rack, or baking them one at a time. This will ensure even baking.
  • Once the cakes are done let them cool completely before decorating.

How to make the best chocolate frosting:

  • Melt butter in a microwave safe dish.
  • Mix in cocoa powder and salt. Alternate stirring in the powdered sugar and milk in increments. I like to do 1 cup powdered sugar, 1 splash of heavy cream, stir and repeat.
  • Stir in vanilla.
  • Make sure to make 2 batches of this recipe!
  • Enjoy!
  • See notes for more frosting info!*

To assemble the cake

  • Once cakes are cooled, level them by cutting off any raised dome structures.
  • Gate your almond bark to make chocolate shavings. I used a cheese grater and grated about half of the large chocolate bar.
  • Place a little bit of frosting on a cardboard cake round and then place your first layer on top of that.
  • Add at least ½ cup of frosting on top of the first layer and spread out into a nice thick even layer. Then repeat with the 2nd layer and 3rd layer.
  • Then gently press the chocolate shavings over the entire cake.
  • Using whipped cream, either canned or homemade (if using homemade use a piping page and tip to get the correct design), pipe on 8 dollops of whipped cream.
  • Place a cherry on each dollop of whipped cream (it might help to dry the cherries off with a paper towel before placing them on the whipped cream).
  • Add a white candle in the middle and now you have a portal cake! Enjoy!


*I used Hershey’s special dark cocoa powder for the cake to make it a dark chocolate cake, but you can use any cocoa powder you have. *I made 2 batches of this to frost the cake. I didn’t just double the recipe and throw all the ingredients together because I wasn’t sure if the consistency would be the same. If you do try that and it is too runny just add more powdered sugar ¼ cup at a time until it is to the thickness desired. If the frosting is too stiff, just add more heavy cream, 1 tbs at a time, until it is less thick. 


Calories: 577kcal | Carbohydrates: 72g | Protein: 6g | Fat: 31g | Saturated Fat: 20g | Cholesterol: 128mg | Sodium: 266mg | Potassium: 123mg | Fiber: 1g | Sugar: 55g | Vitamin A: 812IU | Vitamin C: 1mg | Calcium: 45mg | Iron: 1mg