Square Chocolate Cake (8×8 Cake)
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This Square Chocolate Cake Recipe is rich, moist, and deeply chocolatey. Just the kind of dessert you turn to when you want something comforting and homemade without the effort of layering or decorating. If you love simple, single-layer cakes like my Square Vanilla Cake you’ll be obsessed with this one too. Baked in a classic 8×8 inch square cake pan, this moist chocolate cake is topped with a silky chocolate buttercream frosting for the ultimate small batch chocolate cake!
This Cake? I’m Fully Obsessed.
I’ve baked a lot of chocolate cakes over the years but this square chocolate cake is the one I keep coming back to. It’s just… everything.
The texture is so soft and moist it practically melts in your mouth, but it still holds that light, fluffy crumb that makes each bite feel effortless.
It’s rich and chocolatey without being over-the-top. Comforting but not basic. And honestly? I wasn’t prepared for how good it would be, especially considering how simple it is to make. One bite in and I was fully hooked.
And don’t even get me started on that buttercream. It’s the kind of chocolate frosting that spreads like velvet, hits the perfect sweet spot, and instantly makes the whole thing feel like a bakery cake, minus the fuss.
If you’re looking for a quickchocolate cake you’ll make once and then think about forever… this is it.
Sam x
Ingredients you’ll need
- All-purpose flour
- Baking powder
- Granulated sugar
- Light brown sugar
- Cocoa powder (Dutch-process or natural)
- Instant coffee powder (optional)
- Boiling water
- Extra virgin olive oil
- Eggs
- Vanilla extract
- Salt
- Unsalted butter
- Powdered sugar
- Whole milk
Find the full ingredients, measurements, and method in the recipe card below.
How many people can an 8-inch square cake serve?
An 8-inch square cake can typically be cut into 16 equal squares, making it ideal for serving up to 16 people if each guest receives one square. This portion size works well for both casual gatherings and family events, ensuring everyone enjoys a delightful piece of cake.
Do I have to use instant coffee in the batter?
Nope, it’s totally optional. It won’t make the cake taste like coffee, but it deepens the chocolate flavor beautifully if you do include it.
Can I bake this chocolate cake in a round pan instead of square?
Yes! This recipe can be baked in an 8-inch round cake pan instead of an 8×8 square pan with great results. Just keep in mind that the batter will sit a little deeper in the center of a round pan, which may affect the baking time slightly. Check for doneness 1–2 minutes earlier, and use the skewer test, it should come out clean or with a few moist crumbs. The texture and rise will still be just as soft and delicious.
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Square Chocolate Cake (8×8 Cake)
Ingredients
Method
- Preheat Oven: Preheat oven to 356ºF (180ºC). Line a square 8×8 inch baking pan with parchment paper, set aside. Note: Alternatively, if you have a non-stick pan, liberally grease it with softened/spreadable butter and dust it with a light layer of cocoa powder. This will leave your finished cake with smooth sides.

- Mix dry ingredients: In a medium-size mixing bowl, add flour, baking powder, both sugars and salt. Whisk until well combined and set aside.
- Sift cocoa powder: In a separate large mixing bowl, sift in the cocoa powder.
- Add coffee powder: Whisk the instant coffee with the cocoa powder.
- Add boiling water: Pour in boiling water and whisk until the cocoa dissolves. Set aside to cool slightly for 10 minutes. If it’s still too warm to the touch, leave it for a further 5 minutes, you don’t want the eggs to curdle when added.
- Add wet ingredients: Pour in olive oil, eggs, and vanilla. Whisk for 40 seconds until well combined.
- Combine wet and dry: Add all of the flour mixture and whisk gently until just combined. Be careful not to overmix, stop as soon as no streaks of flour remain. The batter will be thin.
- Pour into pan: Pour batter into the prepared pan.
- Bake: Bake for 28–30 minutes or until a skewer inserted into the middle comes out clean or with only a few moist crumbs.
- Cool: Remove from oven and allow to cool in the pan for 15 minutes.
Carefully remove from the pan and transfer to a wire rack to cool completely before adding the frosting.
- Beat Butter: In a large mixing bowl, beat the softened butter for 2 minutes until creamy.
- Sift Sugar & Cocoa: In a separate bowl, sift together the powdered sugar and cocoa powder to remove any lumps and combine evenly.
- Add Sugar & Cocoa Gradually: Gradually add the sifted mixture to the butter, half a cup at a time, beating well (about 15 seconds) after each addition.
- Add Milk, Vanilla and Salt: Add the milk, vanilla extract and salt, then beat for 1 minute until the frosting is light and fluffy.
- Frost Cake: Once the cake is completely cooled, spread the chocolate buttercream evenly over the cake.
- Serve: Cut into squares and serve. Enjoy!