Step 1

Preheat the oven to 150°C / 300°F (fan/convection) or 160°C / 320°F (standard). Grease and line a 20 cm (8 inch) round cake tin. The cake rises very high when baking, so make sure that the baking paper rises at least 6 cm (2 inches) above the top of the tin.

Step 2

Place chopped butter and chocolate in a large heat-proof bowl. Microwave for 1 minute on high power. Stir well. Microwave for another 30 seconds. Stir until the chocolate is completely smooth and melted. Microwave in further 10 second bursts, if needed, to completely melt the chocolate.

Step 3

Add sugars and instant coffee granules. Stir well. Add milk, eggs and vanilla. Stir until well combined.

Step 4

Sift over flour, cocoa powder, baking powder and salt. Stir until the batter is well combined.

Step 5

Pour into the prepared tin. Bake for 80-90 minutes (1 hr 20 mins - 1 hr 30 mins) or until a skewer inserted in the middle of the cake comes out with only a few moist crumbs clinging to it. Avoid opening the oven door during cooking as much as possible or the cake will sink in the middle.

Step 6

Allow to cool for 20 minutes in the tin before transferring to a wire rack to cool completely.

Step 7

Stir together milk and cream in a small heat-proof jug. Microwave for 1 minute on high power or until it just begins to bubble (but is not boiling over).

Step 8

Place the finely chopped chocolate in a separate small bowl. Pour the hot cream and milk over the chocolate and allow to stand for 5 minutes. Stir together until smooth and well combined. If the chocolate doesn't melt completely, microwave the ganache in 10 seconds bursts until smooth.

Step 9

Using a large serrated bread knife, level out the top of the cake so it is completely flat. Pour the ganache over the top of the cooled cake, using the back of a spoon to spread it evenly over the sides of the cake. Refrigerate for 2 hours or until ganache is firm and matte. The ganache can also set at room temperature (if your house is reasonably cool), but it may take longer.

Step 10

Slice up and enjoy! I find that this cake tastes even fudgier on the second day.