One bowl chocolate fudge

for the cake

100 grams plain flour/hazelnut flour
90 grams caster sugar
15 grams best-quality cocoa powder
1 teaspoons baking powder
¼ teaspoon bicarbonate of soda
⅛ teaspoon salt
2 eggs
35ml sour cream/curd
¼ tablespoon vanilla extract
75ml corn oil
75ml chilled water

for the fudge icing

45grams dark chocolate(minimum 70% cocoa solids)/Nutella
65 grams unsalted butter (softened)
70 grams icing sugar (sifted, necessarily)
¼ tablespoon vanilla extract

METHOD

Preheat the oven to 180°C/gas mark 4.
Butter and line the bottom of a 20cm/8 inch sandwich tin.
In a large bowl, mix together the dry ingredients.
In another bowl or wide-necked measuring jug whisk together all the liquid ingredients.
Add the dry ingredients all at once and mix together on a slow speed until everything is blended and then pour into the prepared tin. The batter will be very liquidy. That's what will make the cake moist.
Bake the cake for 30-40 minutes, or until a cake-tester comes out clean. Cool the cake in its tin on a wire rack for 25 minutes, and then turn the cake out onto the rack to cool completely. Then transfer on to a serving plate.

Icing:
To make the icing, melt the chocolate in the microwave - 1 minute on medium should do it - or in a bowl sitting over a pan of simmering water, and let cool slightly.

In another bowl beat the butter until it's soft and creamy and then add the sieved icing sugar and beat again until everything's light and fluffy. Then gently add the vanilla and chocolate and mix together until everything is glossy and smooth. Ice the top and sides too, spreading and smoothing with a rubber spatula.
Decorate with chocolate chips or hazelnuts.

To serve, boil water in a pan and dip the knife in it, once hot, take the knife out and wipe it with a clean spare cloth and cut a slice and then dip the knife in the water again and repeat.

To refrigerate, always seal the cake from all sides and when taking out of the fridge, make sure you leave it covered at room temperature for atleast half an hour.