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This cake recipe is my family's Texas sheet cake recipe. It is the only chocolate sheet cake you will ever need. Essentially a one-bowl recipe and super quick to whip up. It is super moist, super chocolate and super versatile.
What is Sheet Cake?
Well, sheet cakes are not really a thing in the UK, at least not in the American sense (or size) of the term. Basically a sheet cake is an easy crowd pleasing bake, using a large baking tray known as a sheet pan. This large rectangular cake is fairly thin, and normally topped with frosting. When homemade, the sheet cakes are usually served straight from the pan. They are easily sliced into squares for serving, a lot like brownies, which makes it a great birthday party cake.
In the UK, sheet pans exist, but these are normally smaller than the American counterpart and used for bakes such as Swiss rolls. You don't usually find large sheet cakes ready made and frosted in grocery stores, the way you would in America. In fact, I know many American expats who are willing to travel long distances to get to a Costco, which is one of the few locations in the UK that you can reliably get an American style sheet cake birthday cake.
What Makes a Texas Sheet Cake?
The exact origins of the Texas sheet cake are not known. It is thought to be related to German Chocolate Cake, but baked in a single layer sheet pan rather than stacked round cake layers. It is a popular chocolate sheet cake, most known for being moist and topped with a boiled cocoa frosting.
Making My Chocolate Sheet Cake
Ingredients and Process
For this recipe, you will need:
- Unsalted butter - no need for this to be softened as you'll be melting this.
- Cocoa powder
- Flour - you can use all-purpose flour or plain flour interchangeably here.
- Sugar - either granulated or caster sugar.
- Baking Soda
- Crème fraîche
This cake recipe is essentially a one-bowl recipe and you can make it using just one large saucepan. I opt to use a saucepan and a separate bowl to speed the cooling process.
There are only three steps, which align with the ingredients fairly nicely.
1. Boil: Butter, Water and Cocoa
To begin this recipe, you will add the butter, water and cocoa powder to a saucepan. Heat this over a medium heat and bring these to a boil as your butter melts.
You do not need to work with softened room temperature butter for this recipe, since you will be melting it over a stove top anyway. You can take butter straight from the refrigerator. My recipe calls for 1 cup - in America, this is the same as 2 sticks of butter, in Britain this is 220g (so slightly less than a full 250g block).
The process of boiling the mixture helps to bloom the cocoa, accentuating the flavour for the final product.
Once your mixture boils, remove this from the stovetop and set aside to cool. There are two options for cooling:
- Cool in the pan for 30 minutes and then carry on mixing the rest of the cake batter in the pan.
- Pour into a large bowl to cool more quickly (15 min) and make the remaining batter in the bowl.
2. Add the Sugar, Flour and Salt
Once cooled a bit, add in the sugar, flour and salt. I do this all at once, no need to add in intervals or any particular order.
3. Add Crème Fraîche, Eggs and Baking Soda
The final ingredients can then all be added to the mix. Whisk together until smooth.
If you don't have crème fraîche, you can also use sour cream in place of this for the same effect or substitute with yogurt. You will want something with a bit of acidity to help react with the baking soda and for the flavour in your cake.
Preparing Sheet Pans
This recipe fits in one American standard three-quarters sheet pan or in two 9"x13" sheet pans. If you want to make one 9"x13" sheet pan, simply halve the recipe ingredients and otherwise follow the same process.
I find lining the base of the sheet pan with parchment paper makes it easier to remove slices and removes any fear of the cake sticking.
Since it is standard practice to serve sheet cake straight from the pan, you may want to forego the overhanging parchment for presentation. Simply grease and flour the pan well in advance to help avoid sticking at the end.
Texas Sheet Cake Frosting
So, a Texas sheet cake isn't really a Texas sheet cake without the fudgy chocolate frosting. This boiled cocoa frosting is a standard accompaniment for an old fashioned Texas sheet cake.
The recipe is five ingredients and made in one saucepan.
You will need:
- Cocoa powder
- Unsalted butter - again no need for this to be pre-softened.
- Vanilla extract
- Powdered icing sugar
Place the cocoa powder, butter, vanilla and milk into a saucepan. Melt the butter and bring to a boil.
Remove from the heat and sift in the powdered sugar. Whisk this all together until smooth and then pour over the cakes in their sheet pans while they are still warm.
Smooth the frosting out with a spatula. It will start to set quickly and may look like it is crusting. This won't be a problem, it will even itself out and won't fully set until it cools.
Slice and Serve Sheet Cake
It is best to allow the sheet cake to cool a bit before slicing, if you can restrain yourself! One of the beauties of an old fashioned chocolate sheet cake is that you can easily cut this with a standard spatula - one tool to slice and serve!
FAQs for the Ultimate Chocolate Sheet Cake
You can keep the chocolate sheet cake for several days, covered in cling film at room temperature. Alternatively, you can make this well ahead, and freeze it in its tray. Simply allow to cool, once frosted, cover the tray in cling film and freeze. Allow to defrost before consuming. This is useful if you've made two smaller sheet cakes with the recipe below as you can keep the second for later.
Yes! Though it won't technically be a sheet cake. You can make this same cake recipe as a more traditional cake and use different frostings.
For example, I have made this in a 9" round cake tin and frosted with a dulce de leche buttercream and flaked coconut. I have also used this cake recipe to make smaller round cakes, which I then stacked, covered in chocolate ganache and fondant for a cat shaped finished product (see below images). It is extremely versatile!
Do be aware that the baking times will vary depending on the size of the cake pan being used and how full this is. As this is a very moist cake, you may find that you need to cover the cake pan in aluminium foil to prevent the top from catching. This is particularly true if you choose to make one large 9" cake.
If you like this recipe, you might also like:
- Devil's Food Cake
- Seven Layered Chocolate Cake
- No Bake S'mores Cheesecake
- Mini Chocolate Ganache Cheesecakes
Texas Sheet Cake
Ingredients for Chocolate Sheet Cake
- 1 cup butter 2 sticks or 220g
- 1 cup water
- 4 tablespoon cocoa powder
- 2 cups plain or all purpose flour
- 2 cups sugar
- ½ teaspoon salt
- 2 eggs
- ½ cup crème fraîche
- 1 teaspoon baking soda
Ingredients for Texas Sheet Cake Frosting
- ½ cup butter 1 stick or 110g
- 4 tablespoon cocoa powder
- 6 tablespoon milk
- 1 teaspoon vanilla
- 16 oz powdered icing sugar, sifted
Instructions for Chocolate Sheet Cake
- Add the butter, water and cocoa powder to a large saucepan and heat over a medium heat until the butter has melted and the mixture boils. Remove from the heat to allow to cool for 15-30 minutes.
- Preheat the oven to 350°F (175C/155C Fan) and prepare your sheet pan. This recipe will fit a three-quarter size sheet pan or two 9"x13" sheet pans. Grease and flour this or line with parchment paper.
- Add flour, sugar and salt to the boiled cocoa mixture, whisk to combine.
- Lastly, add the eggs, crème fraîche and baking soda to the mixture and whisk until smooth.
- Pour batter into the prepared sheet pan(s) and bake for about 25 minutes, checking after 20 minutes until a toothpick comes out clean.
- Remove from the oven and cover in the frosting while still warm in the sheet pan.
Instructions for Boiled Cocoa Frosting
- Add the butter, cocoa powder, milk and vanilla to a saucepan and heat over a medium heat until the butter has melted and the mixture boils.
- Sift the powdered icing sugar into the boiled cocoa and whisk until smooth.
- Pour this over your warm cake in the sheet pan(s) and spread evenly.