Chocolate Sheet Cake

4.56 from 9 votes

This chocolate sheet cake is an easy recipe made with everyday ingredients. It's incredibly moist and fudgy with the perfect chocolate flavor.

Prep Time25

Cook Time35

Cooling30

Total Time1 30

Course: Dessert

Cuisine: American

Keyword: 9x13 inch chocolate cake, Chocolate Sheet Cake

Servings: slices

2 cups all-purpose flour (250 grams)
1/2 cup cocoa powder (45 grams)
2 cups granulated sugar (400 grams) use 1 3/4 cup for a slightly less sweet cake
2 teaspoons baking soda
1/2 teaspoon baking powder
1/4 tsp salt
1/2 cup vegetable oil (120 ml)
2 large eggs
2 teaspoons vanilla extract
1/2 cup milk (120 ml) milk - whole milk is best, 2% works too
1/2 cup sour cream (120 ml) or plain Greek yogurt
3/4 cup freshly brewed coffee (180 ml) or boiling water

Preheat the oven to 350F degrees.
Grease a 9x13 inch pan and dust with cocoa powder. Alternatively, line the pan with parchment paper so that there's an overhang around the edges (I recommend lining if you plan not to serve the cake in the pan or freezing the unfrosted cake).
In a large bowl whisk together the flour, cocoa powder, sugar, baking soda, baking powder and salt. If the cocoa is lumpy, be sure to sift it first.
In a separate large bowl, whisk together the oil, vanilla, eggs, milk and sour cream.
Make a well in the middle of the dry ingredients and pour the wet ingredients into the well. Carefully mix together. I always do a few stirs by hand, then start whisking with a wire whisk.
When the ingredients look about 75% combined, pour in the hot coffee. Whisk together vigorously with a wire whisk until you no longer see any lumps or streaks of dry ingredients and the mixture is even (ie the hot coffee isn't sitting on the top of the bowl) - about 1 minute.
Pour the batter into the prepared pan, and bake for about 35 minutes, or until an inserted toothpick comes out clean or with a few cake crumbs. I recommend first checking around 30 minutes, although it may take up to 40 minutes.

In a large bowl, beat the butter until softened.
Sift in 2 cups powdered sugar, along with the sifted cocoa powder, vanilla and salt. Start with the mixer on a low speed and gradually increase to medium speed until combined.
Beat in the rest of the powdered sugar about 1/2 cup at a time, alternating with 1-2 tablespoons of cream (or milk) until the desired consistency and sweetness is reached.
Ensure that the cake has fully cooled, then frost with a flat edge knife. Optionally, decorate with sprinkles.

Cocoa: Use Dutch processed cocoa (sometimes called Dark or Specialty Dark) for best results.
Room Temperature Ingredients: The eggs, milk and sour cream should be at room temperature before getting started.
Sour Cream: Can be replaced with plain, Greek yogurt. Do not use vanilla yogurt.
Hot Coffee: This can be replaced with boiling water.
Storage: Unfrosted cake can be covered and stored at room temperature overnight. Frosted cake can be stored at room temperature for up to 8 hours, then stored covered in the fridge for up to 4 days. After being in the fridge, let the cake sit on the counter at room temperature for about 30 minutes before enjoying.
Nutrition: Details provided are an estimate only and based on 1 slice of cake with frosting, assuming the recipe yields 18 uniform pieces.