Preheat the fan oven to 160°C (320°F). Grease and line the bases of 2 8-inch round cake tins.

Place the 2 eggs, 175 ml olive oil or neutral oil, and 175 ml buttermilk in a large mixing bowl. Whisk until smooth.

Dissolve 5 g instant coffee in 170 ml boiling water. Pour the coffee mixture into the wet mixture and whisk to combine.

Sift 230 g plain flour, 80 g cocoa powder, 10 g bicarbonate of soda, and 5 g baking powder into a second large mixing bowl. Add 5 g sea salt.

Add 125 g caster sugar and 125 g light brown sugar to the dry mixture. Whisk until evenly combined.

Pour the wet mixture into the dry mixture. Whisk only until the batter is smooth and no dry flour remains.

Divide the batter evenly between the 2 prepared cake tins. Bake for 35 minutes.

Remove the cakes from the oven when a skewer inserted into the centre comes out clean or with a few moist crumbs. Cool in the tins for 10 minutes.

Turn the cakes onto a cooling rack. Leave them to cool completely before assembling.

Finely chop 150 g dark chocolate 70% and 50 g milk chocolate 55%. Place both chocolates in a heatproof large mixing bowl.

Heat 300 ml double cream with 1 tablespoon malt extract until steaming but not boiling. Pour the hot cream over the chopped chocolate.

Leave the ganache undisturbed for 2 minutes. Stir with a rubber spatula until glossy and completely smooth.

Let the ganache stand until thick and spreadable. Spread half over one cooled cake layer.

Place the second cake layer on top. Spread the remaining ganache over the top of the cake.

Serve at room temperature, or warm an individual slice briefly in the microwave. Serve with cold cream if desired.