Chocolate Sheet Cake {With Cake Mix}

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Soft, moist, easy chocolate sheet cake recipe with fudge chocolate cream cheese frosting, homemade with simple ingredients. This delicious birthday cake starts off with a cake mix and is topped off with sprinkles.

This is such a simple recipe and the best part is that it can easily be used to serve a lot of people. If you want to see some similar sheet cakes, check out my Yellow Sheet Cake (With Cake Mix) or Texas Sheet Cake . The poured chocolate icing from that recipe would work great in this recipe, too! Also, if you are fond of using boxes to make delicious desserts, be sure to check out this collection of Easy Cake Mix Recipes (Desserts).

Easy Chocolate Sheet Cake With Cake Mix in Gray Baking Tray With One Slice Removed
Closeup Shot of Slab Cake in Gray Baking Tray

How to make easy chocolate sheet cake recipe with cake mix? 

  1. Beat eggs- Until fluffy and bubbly.
  2. Mix in- Sour cream and melted butter.
  3. Add in– Chocolate cake mix, cocoa powder, and coffee.
  4. Pour batter– Into rectangle cake pan.
  5. Bake– Until an inserted toothpick comes out clean.
  6. Prepare frosting- While cake is baking.
  7. Spread frosting– All over the cake.
  8. Toss sprinkles– On top of the cake.

Key ingredients

  • Cake mix– Use chocolate box mix.
  • Sour cream– Adds so much moisture.
  • Coffee– Should be strongly brewed
  • Cocoa powder– Intensifies the overall chocolate flavor
  • Eggs– Should be large sized.
  • Butter– Should be unsalted and melted.
Slice of Chocolate Sheet Cake With Fudge Chocolate Frosting and Sprinkles on White Plate

What makes Texas sheet cake different than regular chocolate cake?

Unlike the typical cake counterpart, the sheet cake is thinner and spreads out over more space in a more shallow, wide pan. The regular cake is thick and usually uses a deeper pan. Regular cakes are also used to stack on top of one another, but the sheet cake stands alone with frosting or other toppings.

Why do you add sour cream in cakes? 

I like to add sour cream because it makes the cake extra moist while not adding too much liquid. You still get that nice, thick cake.

Sheet cake sizes

There are several different size options for sheet cake. The most popular is usually a 9″ x 13″ cookie tray since many have these for baking already. However you can also use other sizes, which can vary by a few inches, depending on what pan you have. Here are the typical sizes used for sheet cakes:

  • Full- 18″ x 24″ and serves approx. 48-96 people.
  • Half- 11″ x 15″ or 18″x 13″ and serves approx. 18-40 people.
  • Quarter- 9″ x 13″ and serves approx. 12-32 people. The recipe below is for this size.

Sheet cake decorating ideas

Wafer Paper Flowers– Add these Easy Wafer Paper Flowers in different sizes on the cake in a cascading pattern.

Fondant flowers- Try these Easy Fondant Daisies, Easy Flower Cupcakes {Fondant Pansy}, Fondant Flower CakeHow To Make Fondant Flowers,  or Fondant Roses.

Sugar flowers– Like these dainty Royal Icing {Sugar Flowers} for an elegant touch.

Piped flowers– Try these Buttercream Flowers (Russian Piping Technique), or follow this easy tutorial for Russian Piping Tips. You can even make a Rosette Cake (Buttercream Icing).

Edible leaves- Try these homemade Chocolate Leaves.

Sprinkles-These simple Homemade Sprinkles make a fun addition to the cake. There are lots of colors and shapes to choose from.

Candies- So many shapes and colors that you can arrange in any way you like. Check out this Easy Candy Cake (With Halloween Leftovers) and this Birthday Cake for inspiration. I love using Sixlets and marshmallows.

Cereal– Lots of variety in the market these days to create any design you like. Check out how I decorated this Cereal Cake.

Bows– These Easy Fondant Bows are so cute and easy too.

Tie-Dye Frosting– Follow the frosting instructions in this Easy Tie Dye Cake recipe.

Fork Full Of Cake on White Plate

Sheet cake frosting ideas

Variations for best, old fashioned chocolate sheet cake with fudge frosting

Add nuts- Chop or crush nuts until they are broken down into small pieces and sprinkle on top of frosted cake. You can use peanuts, pecans, walnuts, or almonds.

Top with fruits- I especially like to add fresh berries, such as raspberries, blueberries, blackberries and sliced strawberries. You can also use pineapple, mango, or other fruits that pair well with your own variations.

Use a different extract- Substitute vanilla extract with almond, maple, coconut, orange, or mint extracts.

Add various chocolate chips- Such as milk or semi-sweet chocolate, white chocolate, butterscotch, or peanut butter for a flavor twist.

Add mini candies or chopped candies- Like mini M&Ms, chopped Heath bars, Butterfingers, or Snickers.

Tips and techniques for slab cake

Don’t over-mix batter- There will be a few lumps when mixing ingredients together, but don’t worry about them, because over-mixing can cause you cake to collapse during baking.

Grease and flour cake pan- Because otherwise your cake will stick to the pan and you won’t be able to cut out nice slices for your guests.

Use a spatula to spread frosting- And create a swirly pattern for a nice looking finish.

How do you know if the cake is done baking? Insert a toothpick into the center of the cake and if it comes out clean it is done. If it comes out gooey, it still needs to to cook a few more minutes.

Save time- By making the chocolate frosting while the cake bakes and cools off.

Ingredients should be at room temperature- Because they blend together better and more evenly.

Use unsalted butter- Because it keeps the cake from becoming a salty mess.

Sour cream substitute– Thick full fat Greek yogurt can be used but I have noticed that it adds a subtle tanginess that I don’t like much.

Unfrosted Freshly Baked Chocolate Cake in Gray Baking Tray


Refrigerator– Leftovers can be stored in a sealed container for up to 3 days. 

Freezer- Unfrosted cake and frosting can be stored separately in sealed containers for up to 1 month. Before serving, thaw in the fridge overnight and then, decorate as per instructions below.

More doctored cake mix recipes

Slice of Easy Chocolate Sheet Cake With Cake Mix Frosted With Fudgy Chocolate Icing And Sprinkles on White Plate
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Easy Chocolate Sheet Cake (With Cake Mix)

Prep Time: 10 minutes
Cook Time: 40 minutes
Total Time: 50 minutes
Soft, moist, easy chocolate sheet cake recipe with chocolate frosting, homemade with simple ingredients. This delicious birthday cake starts off with a cake mix.
Yield: 12 Slices



  • In a large mixing bowl, add eggs and beat until fluffy and bubbly.
  • Then, add sour cream, melted butter and mix until combined.
  • Add chocolate cake mix, cocoa powder, coffee and mix until just combined. There will be a few lumps but don't worry about them. Please don't over-mix!
  • Pour batter in a greased and floured rectangle cake pan (Dimensions: 9×13).
  • Spread batter evenly with a spatula.
  • Bake at 350 degrees F for 30-40 minutes or until an inserted toothpick in the center comes out clean.
  • While the cake is baking and cooling, prepare the chocolate frosting.
  • Spread frosting on top of the cake and use a spatula to create a swirly pattern.
  • Toss sprinkles on top of the cake. Enjoy!


  • Read all my tips above.
  • Leftovers can be stored in a sealed container in the fridge for up to 3 days. 


Calories: 373kcal, Carbohydrates: 53g, Protein: 4g, Fat: 18g, Saturated Fat: 7g, Polyunsaturated Fat: 3g, Monounsaturated Fat: 7g, Trans Fat: 0.1g, Cholesterol: 54mg, Sodium: 408mg, Potassium: 243mg, Fiber: 2g, Sugar: 37g, Vitamin A: 208IU, Vitamin C: 0.1mg, Calcium: 75mg, Iron: 2mg
Course: Dessert
Cuisine: American
Calories: 373
Author: Abeer Rizvi

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