Step 1

Cake: Grease a deep 26.5cm x 33cm, 14-cup capacity baking dish.

Step 2

Line base with baking paper.

Step 3

Combine water, sugar, butter, cocoa and bicarb soda in a large saucepan.

Step 4

Stir over heat, without boiling, and until sugar is dissolved.

Step 5

Bring to the boil, and then simmer, uncovered, for approximately 5 minutes.

Step 6

Transfer to a large bowl of an electric mixer and cool for approximately 10 minutes.

Step 7

Add flour and eggs, and beat until mixture is smooth.

Step 8

Pour mixture into prepared dish.

Step 9

Bake at 180C for approximately 50 minutes.

Step 10

Stand cake for approximately 10 minutes before turning onto a wire rack to cool.

Step 11

Fudge frosting: Combine butter, water and caster sugar in a pan, stirring over heat, without boiling, until sugar is dissolved.

Step 12

Add icing sugar and cocoa into a separate bowl, gradually stir in hot butter mixture. Cover and refrigerate until thick.

Step 13

Beat with wooden spoon until mixture is spreadable.

Step 14

Spread cake with frosting.