Recipe video above. This cake is rich, very chocolatey and super moist! It's based on a brownie / mud cake recipe - but with a bit of extra rise so it's not as dense and gooey. This recipe is easy and it's virtually foolproof - it is VERY forgiving! It's not very tall because it's so rich and it's a single layer cake.
Preheat oven to 150C/300F (standard) or 130C/265F (fan). Grease a 22 cm / 9" springform cake pan and line with parchment / baking paper.
Melt butter and chocolate: Place butter and chocolate in a heatproof bowl. Microwave 3 x 30 seconds on high, mix in between, until melted. Mix.
Oil, vanilla & Sugar: Add oil, vanilla and sugar, mix to combine (this brings down batter temp).
Eggs: Add eggs and mix until combined.
Dry Ingredients: Sift cocoa, baking powder and flour (and coffee, if using) directly into the bowl. Mix until smooth, batter will be thin. Some small lumps is ok.
Hot water: Add hot water. Mix until incorporated.
Bake: Pour into the cake tin and bake for 1 hour or until a skewer inserted into the centre comes out moist but clean. Check at 50 minutes. The surface will crack (sometimes badly!) but sill subside when it cools and gets covered with frosting so don't stress!
Cool: Remove sides from the cake pan and transfer to a cooling rack to cool. Cool completely before carefully handling to remove base (Note 7).
Ganache (Note 8)
Place chocolate and cream in a heatproof bowl. Microwave 3 x 30 seconds, mixing in between, until chocolate melts. DO NOT let cream come to boil.
Stir chocolate until smooth. Refrigerate for 1 to 2 hours or until thickened to a spreadable consistency like peanut butter.
Spread over the cake - tops and sides. Use a teaspoon in a swirling motion to achieve the textured surface you see in the photos.
1. Chocolate - use any dark or semi-sweet chocolate for best results - flavour, texture, colour. I use chips or melts for everyday purposes, but for company I use good quality block chocolate and chop it myself into fine little pieces (see Chocolate Ganache recipe for directions).Milk chocolate and white chocolate will not set firmly enough because they are softer chocolates. Follow the Chocolate Ganache recipe to make milk or white chocolate ganache for this cake. Don't use eating chocolate - it doesn't melt properly and is too thick for batter.2. Sugar - Normal white / granulated sugar works ok too. Even brown sugar works3. Cocoa - Ordinary, unsweetened cocoa powder is what I usually use. To give it an even deeper chocolate flavour, use good quality Dutch processed cocoa powder.4. Self raising flour can be substituted in place of plain flour + baking powder.5. Coffee - a touch of coffee brings out the chocolate flavour but doesn't make the cake taste like coffee. Because I don't use coffee granules for day to day purposes, I usually do not have it on hand so I don't use it most of the time. The other option is to use a hot cup of coffee in place of the water - same quantity (1 cup / 250 ml).6. Cream - you must use cream with 30%+ fat in order for the ganache to set. Heavy / thickened cream is ideal. Low fat will not work. Some pouring creams (ie not whippable) are lower fat and also will not work.7. Handling: Because the cake is so fudgy, it's delicate so handle gently. The cake is more delicate when warm (as all cakes are) so don't try to remove the base until it's completely cool. If you don't have a springform pan, just cool the cake in the pan.8. Ganache - pourable when warm, thickens to a spreadable consistency when cooled (which is what you want to frost this cake) and when refrigerated for a few hours, hardens to a chocolate truffle consistency. If you leave it in the fridge for slightly too long i.e. too hard to spread, just microwave for 10 seconds to soften then mix.9. Different Measures in Different Countries: Measuring cups and teaspoons differ slightly between America, Canada and most of the rest of the world. For most recipes, the difference is not enough to affect the outcome. However, for baking recipes it can mean the difference between success and an epic fail.Every baking recipe on my site is cooked using each Imperial and US measurements, and this one is no exception. It works as written regardless of what country you are in (except Japan, see note below). As noted in post, it is actually quite forgiving because it's so moist and fudgey. Japan: If you are in Japan, please ensure you weigh the flour, sugar etc. Do not use Japanese measuring cups, they are too small.10. Easy Chocolate Fudge Cake Nutrition per slice assuming this serves 12. This is a VERY big slice!