Make the frozen ganache the evening before if possible; however, if you are short of time, two hours in the freezer should do the trick. To make the ganache, melt the chocolate with the milk in a heatproof bowl over a pan of gently simmering water, making sure the base of the bowl doesn’t touch the water. Stir occasionally with a small whisk or spoon until the chocolate has melted and is combined with the milk. (Alternatively, put the ingredients in a microwave-safe bowl and microwave at full power for 30 seconds. If there are still lumps of chocolate, put it back into the microwave in 10-second blasts, stirring each time, until completely combined and smooth). Pour the ganache into an ice cube tray and put into the freezer. Leave to freeze for at least two hours.
Thirty minutes before you want to serve your fondants, preheat the oven to 180°C (160°C fan, gas 4). Take four small individual pudding moulds or ramekins that will comfortably hold an ice cube, grease them with oil and dust with a layer of cocoa powder.
Sift the flour, cocoa powder, bicarbonate of soda and salt in a large mixing bowl. Using a whisk, mix the sugar into the dry ingredients. In a separate bowl mix together the milk, plus 150ml of warm water, the coffee, vinegar, flaxseed and oil. Using the whisk, mix the wet ingredients into the dry ingredients until the batter is combined.
Fill each pudding mould to about a quarter with the fondant mixture, then place a frozen cube of ganache on top. Cover the ganache with more fondant mixture until the pudding mould is just over half full. Gently tap the moulds on the work surface to remove any air bubbles. Put the filled moulds onto a baking tray and bake in the centre of the oven for 14 minutes — do not be tempted to open the oven door!
When the timer goes, remove from the oven immediately. Gently release the sides of each pudding using a small round-bladed knife. Put a small serving plate on top of the mould and flip upside down so that the plate is now the right way up. Carefully lift off the pudding mould. Serve immediately with an extra dusting of cocoa powder.
Notes
For an extra twist, you can add a teaspoonful of peanut butter in the centre of each fondant with the frozen ganache.